School Science Lessons
(topic16)
2024-09-16 Organic chemistry
Contents 16.1.0 Organic chemistry 16.1.5 Acetal 16.2.0 Acyclic hydrocarbons 16.3.0 Alkanes, CnH2n+2, paraffins 16.4.0 Alkenes, CnH2n, olefins 16.7.0 Alkynes, CnH2n-2, acetylenes 16.5.0 Aromatic hydrocarbons, Arenes 16.6.0 Alcohols, phenols, thiols 16.1.9 Bleaches 16.1.6 Ethers 16.1.7 Ethyl cellulose 16.8.0 Fractional distillation of crude oil 16.7.2 Imides 16.7.3 Imines 16.11.0 Isothiocyanates 16.7.6.1 Melamine 16.9.0 Mercaptans 16.7.4 Methylamine ionization reaction 16.7.5 Nitrosamines 16.7.6 Nitriles 16.7.7 Nitrites 16.7.8 Nitroalkanes (nitroparaffins) 16.7.9 Octane number 16.7.10 Organic salts 16.3.5 Oximes 16.1.13 Prepare triodomethane, (iodoform) 16.1.8 Prepare trichloromethane gas (chloroform) 16.1.10 Reaction of ethyl alcohol with bleaching powder 16.7.14 Phosphorous compounds 16.7.16 Saturated hydrocarbons 16.10.0 Sulfur organic compounds 16.1.0 Organic chemistry See diagram 16.0.0: Organic chemistry functional groups. See diagram 16.0.1: Tetrahedral geometry of carbon, methane molecule, isobutyl alcohol.
Organic chemistry is the chemistry of carbon compounds.
Hydrocarbons contain carbon and hydrogen only.
The main types are the alkanes, alkenes and alkynes.
In alkenes and alkynes, addition reactions occur at the double bonds = or triple bonds ≡.
Triple bond (has 6 electrons in the bond), e.g. Carbon monoxide, C≡O.
Be careful! When heating organic chemicals, do not point the test-tube towards anyone!.
Organic compounds may suddenly vaporize and spurt out of the test-tube!.
1. Classification by molecular framework
* Acyclic compounds have chains of unbranched or branched carbon atoms.
* Carbocyclic compounds have rings of carbon atoms.
* Heterocyclic compounds have rings of carbon atoms with one atom in a ring not carbon, e.g. O, N, S.
2. Classification by functional group, e.g. hydroxyl group, OH, is characteristic of alcohols.
Organic compounds 16.1.1 Addition reactions 16.1.2 Oxidation reactions, loss of electrons 16.1.3 Reduction reactions, gain of electrons 16.1.4 Substitution reactions (displacement reactions) 16.2.0 Acyclic hydrocarbons
| Methane | Ethane | Propane | Butane | Pentane | Hexane | Heptane | Octane | Nonane | Decane | Acetylenes | aliphatic compounds | alkanes | alkenes | alkyl groups | alkyl radicals | alkynes | olefins | paraffins | 16.2.1 Acyclic hydrocarbons, alkanes, alkenes 16.3.1 Alkanes CnH2n+2, paraffins 16.5.0 Aromatic hydrocarbons, Arenes 16.2.4 Cycloalkanes 16.6.1.0 Ethane, C2H6, CH3CH3 16.6.2.0, Propane, C3H8 16.6.4.0, Butane, C4H10 16.6.5.0 Pentane, C5H12 16.6.6.0 Hexane, C6H14 16.6.7.0 Heptane, C7H16 16.7.9 Octane number 16.7.9 Octane number 16.2.6 Octadecan-1-ol 16.2.7 Octanol 16.3.0 Alkanes CnH2n+2, paraffins
Alkanoic acids, RCOOH, -oic acids 16.3.1 Alkanes CnH2n+2, paraffins 16.2.1 Acyclic hydrocarbons, alkanes, alkenes 16.3.3 Friedel-Crafts reaction 16.7.8 Nitroalkanes (nitroparaffins) 16.3.5 Oximes 16.4.0 Alkenes, olefins 16.4.1 Alkenes, CnH2n, olefins 16.4.2 Ethene 16.4.3 Prepare ethene 16.4.4 Dienes, diolefins 16.6.0 Alcohols, phenols, thiols 16.6.1 Alcohols 16.6.2 Alcohols, primary, secondary and tertiary aliphatic alcohols 16.6.3 Butanol 16.6.4 Butyl glycol 16.6.5 Dihydric alcohols, glycol 16.6.6 Ethanol 16.6.7 Fatty alcohols 16.6.8 Methylated spirits Naphthols 16.6.10 Nitroglycerine (UK), nitroglycerin (USA) 16.6.11 Nitrocellulose, gun cotton 16.6.12 Phenols 16.6.13 Propanol 16.6.14 Pyrogallol 16.6.15 Resorcinol 16.6.16 Sodium ethoxide, Prepare 16.9.4 Thiols (mercaptans) 16.6.17 Triclosan, organohalogens 16.6.18 Trihydric alcohols, glycerol 16.7.0 Alkynes, CnH2n-2, acetylenes
Alkynes (acetylenes): aliphatic hydrocarbons which have one or more triple bonds.
Alkyne, R1-CC-R2 (triple bond C≡C bond 6 electrons, e.g. acetylene, HC≡CH
Alkyne, Prefix: alkynl-, Suffix: -yne (no principal functional group), (acetylenes)
1. acetylenes: ethyne (acetylene) C2H2, HC≡CH, isoprene, methylene
Suffix: (-yne), for C≡C, (acetylenes), are unsaturated hydrocarbons with at least one triple bond (≡) between C atoms.
Alkynes decolorize acidified potassium permanganate solution and bromine solution.
2. The cycloalkynes are closed chain, non-aromatic forms, e.g. cyclooctyne C8H12, the smallest form. 16.8.0 Fractional distillation of crude oil 16.8.1 Fractional distillation of crude oil Asphalt 16.8.2 Diesel oil 16.8.3 Hydraulic fluid 16.8.4 Kerosene 16.8.4 Lubricating oil 16.8.6 Mineral oil 16.8.7 Naphtha 16.8.8 Paraffin wax 16.8.9 Petrol 16.8.10 Petroleum gas 16.8.11 Residuals 16.9.0 Mercapans 16.9.1 Allyl mercaptan 16.9.2 Ethyl mercaptan 16.9.3 Methyl mercaptan 16.9.4 Thiols (mercaptans) 16.10.0 Sulfur organic compounds
Sulfur compounds (For the "thio" prefix, replace oxygen by sulfur, e.g. thiobenzamide PhC(=S)NH2. 16.10.1 Allicin 16.10.2 Alliin 16.10.3 Diallyl sulfide 16.10.4 Diallyl disulfide 16.10.5 Diallyl trisulfide 16.11.0 Isothiocyanates 16.10.7 Methanethiol from asparagus 16.10.8 Phenothiazine 16.10.9 Siloxanes 16.10.10 Sulfides 16.10.11 Sulfonium compounds 16.10.12 Sulfoxide 16.10.13 Thiocyanates 16.10.14 Thiophene 16.1.1 Addition reactions
An addition reaction occurs when an atom or atoms are added to a double bond or triple bond unsaturated molecule to fom a new molecule.br>
For example, (hydrogenation):
CH2=CH2 (g) + H2 (g) --> CH3CH3 (g)
ethene + hydrogen --> ethane (Pt catalyst) 16.1.2 Oxidation reactions, loss of electrons
Primary alcohols can be directly oxidized to aldehydes or carboxylic acids.
Primary alkanols (alcohols) -CH2-OH --> alkanals (aliphatic aldehydes)
Example: CH3OH + O2 --> CH2O + H2 (Pt catalyst)
Oxidation of methanol to methanal using a platinum catalyst
CH3OH + O2 --> 2HCHO + 2H2O
methanol + oxygen --> methanal + water
Alkanals --> alkanoic acids, e.g. butanoic acid, CH3(CH2)2COOH 16.1.3 Reduction reactions, gain of electrons
Alkanals (aliphatic aldehydes) --> primary alkanols (alcohols), -CH2-OH
Experiment
Add drops of formalin to a test-tube one quarter filled with Fehling's A and B solutions and heat to boiling.
Note the yellow then orange then red precipitate of copper (I) oxide.
The copper from the copper (II) sulfate solution has been reduced from copper (II) toCopper (I). 16.1.4 Substitution reactions, (displacement reactions)
A substitution reaction occurs when an atom or group in a molecule is replaced by another atom or group.
For example, (chlorination, halogenation): Methane with chlorine
Be Careful! Dangerous experiment!
When a mixture of an alkane and chlorine gas are stored at low temperature in the dark no reaction occurs.
At high temperatures or in sunlight, a substitution exothermic reaction, "chlorination" produces chloromethane, and HCl.
CH4 + Cl2 --> CH3Cl + HCl
Excess chlorine can produce dichloromethane, trichloromethane, and tetrachloromethane.
A mixture of chlorine and methane explodes violently in direct sunlight forming hydrogen chloride and free carbon.
BE CAREFUL! Do not mix chlorine and methane!
CH4 (g) + 2Cl2 (g) --> C (s) + 4HCl (g) + energy
Chloromethane, CH3Cl, (methyl chloride)
Dichloromethane, CH2Cl2, (methylene chloride)
Trichloromethane, CHCl3, (chloroform)
Tetrachloromethane, CCl4, (carbon tetrachloride) 16.1.5 Acetal
Acetal, C6H14O2, (1,1-diethoxyethane), diethyl acetal, acetaldehyde diethyl acetal, clear colourless liquid, pleasant odour, slightly soluble in water.
It is toxic, and a narcotic in high concentrations.
It occurs in garden onion, Allium ampeloprasum, and Citrus reticulata.
It is used as a flavouring ingredient in fruit, rum, whisky. 16.1.6 Ethers
See: 1.13 List of ethers
Ethers have two hydrocarbon groups linked by one oxygen.
Ethers have compounds in the form: R1OR2 (R not equal to H), where R1 may or may not be the same as R2, e.g. the anaesthetic diethyl ether. "ether".
Ethers (ROR'), CnH2n+2O), alkyl ethers, ethoxyethane ether, e.g. dimethyl ether CH3OCH3. 16.1.7 Ethyl cellulose
Ethyl cellulose, C20H38O11, cellulose ethyl ether, "Aquacoat", food additive emulsifier E462
It is prepared from cellulose in wood and chemically ethylated, (i.e. some hydroxyl groups converted to ethyl ether groups).
It is used as a food stabilizer and thickening agent, filler, dietary fibre, anti-clumping agent, emulsifier.
Ethyl cellulose is no longer permitted as emulsifier in the EU, because it can be fermented in the large intestine toCause bloating, constipation and diarrhoea. 16.1.8 Prepare trichloromethane gas (chloroform) 16.4.13 Trichloromethane, (chloroform), CHCl3 See diagram 16.1.7: Prepare chloroform.
Use a gas mask and gloves.
Put 640 mL of up to 10% bleach, (sodium hypochlorite), and 10 mL acetone, in the refrigerator, or
Put 1 cup of bleach and 1 tsp. acetone in the refrigerator.
(Use acetone cleaning solvent, not nail polish remover).
Remove the bleach and acetone, put the bleach solution in a glass jar, stir in ice cubes, and leave to stand for 30 minutes in a fume hood.
If the bleach soltion becomes cloudy and gives of vapour, do not smell it.
Add the acetone to the bleach solution and while stirring with a mixing stick.
The reaction is exothermic, so leave toCool and observe a white powder or bubble of chloroform at the bottom of the jar.
Pour off the liquid over the chloroform and transfer to a separation funnel to extract the chloroform.
The haloform reaction:
Reaction of acetone with bleaching powder
3NaOCl + (CH3)2CO --> CHCl3 + 2 NaOH + CH3COONa
sodium hypochlorite + acetone --> chloroform + sodium hydroxide + sodium acetate
Chloroform prepared in the above way is distilled to purify it, some magnesium sulfate may be added.
Add 1% ethanol to stabilize the chlorofom if exposed to UV light and oxygen, to avoid break down to phosgene gas.
2 CHCl3 + O2 → 2 COCl2 + 2 HCl
chlorfoform + oxygen --> phosgene + hydrochloric acid See 16.2.2: Chlorinated hydrocarbons, haloalkanes.
Bleaching powder is usually a mixture of calcium chlorate (I) [basic calcium chloride, calcium hypochlorite ( Ca(OCl)2], calcium chloride and calcium hydroxide.
It is prepared by passing chlorine gas through a calcium hydroxide solution.
Calcium chlorate (I) oxidizes ethanol to ethyl aldehyde.
Aldehydes or ketones have a hydrogen atom attached to the carbon atom attached to the carbonyl group, C=O.
This hydrogen atom can be replaced by a halogen atom to form halogen compounds.
If a molecule contains three hydrogen atoms, e.g. ethanol and propanone (acetone) molecule, a trihalide may be formed, e.g. trichloromethane, (chloroform, CCl3).
H3C-C(O)-R + 3OX --> X3C-C(O)-R.
ketone or aldehyde hypochlorite + oxygen --> trihalide.
The trihalide decomposes in a basic solution to a haloform, (CHX3),
e.g. CHCl3C-C(O)-R (l) + OH - (aq) --> CHCl3 (l) + RCOO - (aq). 16.1.9 Bleaches
A bleach can cause animal fibres or cloth to lose colour and become white.
Exposure to sunlight can cause bleaching.
A bleach is a chemical to remove colour or whiten fabric.
Sodium hypochlorite solution is called "liquid bleach".
A formulation containing calcium hypochlorite is called a bleaching powder"
Most bleaches are oxidizing agents, so the powerful oxidizer chlorine is the active agent in many leaches as a hypochlorite, to release chlorine.
Non-chlorine bleaches are usually peroxides, e,g, hydrogen peroxide, sodium percarbonate, and sodium perborate.
Sulfur dioxide, is used to bleach wool.
Sodium and calcium hypochlorite are used primarily as household bleaching agents or disinfectants..
They are components of commercial bleaches, cleaning solutions, and disinfectants for drinking water and waste water purification systems and swimming pools..
Sodium hypochlorite, NaClO, NaOCl, known as "bleach"or "chlorine bleach" is used dissolved in water for domestic bleaching of clothes.
It is a clear, green to yellow liquids with an odour of chlorine.
Calcium hypochlorite, Ca(ClO)2, Ca(OCl)2, calcium hypochloride, is a white solid that readily decomposes in water releasing oxygen and chlorine.
Calcium hypochlorite is a white granular solid, (or tablets compressed from the granules, with an odour of chlorine, toxic, irritating to the skin.
It is used for water purification, disinfectant for swimming pools, for bleaching paper and textiles.
Bleaches used in swimming pools 18.7.2.4 Dichlor 18.7.2.2.1 Calcium hypochlorite, Ca(OCl)2 18.7.5 Available chlorine 18.7.15.1 Green hair and faded hair from swimming pools
NaOCl, NaClO) is commonly known in a dilute aqueous solution as bleach or chlorine bleach. 16.1.10 Reaction of ethyl alcohol with bleaching powder Be careful! Do not allow any flames in the laboratory!.
Grind together in a mortar and pestle 5 g bleaching powder and 10 mL water.
Put the mixture into the test-tube of the gas preparation apparatus.
Cool the test-tube.
Add either 4 mL ethanol in 2 mL water or 4 mL propanone (acetone) in 2 mL of water.
Swirl the contents of the test-tube and keep it cool.
Use an electric water bath to warm the temperature to 55 oC.
Water and trichloromethane condense in the receiving test-tube leaving a calcium salt solution in the test-tube.
Add water to the distillate and separate the trichloromethane with a separating funnel.
C2H5OH (l) + Cl2 (g) --> CH3CHO (l) + 2HCl (aq).
ethyl alcohol + chlorine --> ethyl aldehyde + hydrochloric acid
CH3CHO (l) + 3Cl2 (g) --> CCl3CHO (l) + 3HCl (aq).
ethyl aldehyde + chlorine --> trichloroacetaldehyde + hydrochloric acid.
2 (l) + Ca(OH)2 (aq) --> 2CHCl3 (l) + (HCOO)2Ca (aq).
trichloroacetaldehyde + calcium hydroxide --> chloroform + calcium formate
(Chloral, Cl3CCHO, C2HCl3O, trichloroacetaldehyde, trichloroethanal, colourless oily liquid, penetrating odour irritant, toxic, is used to make pesticides). 16.2.1 Acyclic hydrocarbons, alkanes, alkenes, alkynes See diagram 16.1.1: Alkanes, alkenes, alkynes.
Alkanes, alkenes, alkynes or their derivatives are aliphatic compounds, i.e. non-cyclic organic compounds.
molecules have carbon atoms in chains, but not in rings.
The chains may be unbranched or branched.
Aromatic compounds contain a benzene ring in the molecule.
Hydrocarbon compounds contain only hydrogen and carbon.
Hydrocarbons are usually colourless and have low solubility in water.
Crude oil is a mixture of hydrocarbons.
Hydrocarbons may be saturated, i.e. have only single bonds, or
unsaturated, i.e. contain multiple bonds, e.g. double bond =, or
triple bond, e.g. carbon monoxide, C≡O. Iodine value, the number of grams of iodine absorbed by 100 g of fat or oil, to indicate the amount of unsaturated acids. 16.2.4 Cycloalkanes
Cycloalkanes, CnH2n, cycloolefins, cyclanes, polymethylenes, cycloparaffins, saturated carbon rings
Cycloalkanes are saturated hydrocarbons with a ring of carbon atoms, e.g. the position of branches depends on the alphabetical order of the branch names.
So that highest in order is attached toCarbon 1, e.g. 1-ethyl-2-methylcyclopropane.
Cyclopropane C3H6, colourless gas, former anaesthetic, petroleum odour, is easily ignited, may cause frostbite, containers may explode.
Cyclobutane C4H8, tetramethylene, condenses to liquid at 13 oC, insoluble in water, containers may explode.
Cyclopentane C5H10, pentametylene, colourless liquid, flash point -37 oC, is insoluble in water.
Cycloheptane C7H14, heptamethylene, colourless oily liquid, flash point 16 oC, narcotic effect
Cyclooctane C8H16, octamethylene 16.2.6 Octadecan-1-ol, C18H38O
Octadecan-1-ol, stearyl alcohol, C18H38O, CH3(CH2)17OH, long-chain primary fatty alcohol
It is used for skin care, and occurs in Camellia sinensis.
Use octadecan-1-ol for melting point curve experiments. 16.2.7 Octanol, CH3(CH2)7OH
or 1-Octanol, CH3(CH2)7OH, C8H18O, CH3(CH2)6CH2OH, CH3(CH2)5CH(OH)CH3, octyl alcohol, n-octyl alcohol, octan-1-ol, caprylic alcohol, Flammable 3.10.0 Poisons and First Aid: See Octanol. 16.3.1 Alkanes CnH2n+2, paraffins
Alkanes (paraffins): aliphatic hydrocarbons with only single bonds, i.e. just C-C, C-H single bonds
Alkanes, cyclohexane, heptane, hexane, liquefied petroleum gas (LPG), octane, pentane, petroleum spirit
Alkanes: methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane
The first 10 unbranched alkanes and molecular formula:
methane CH4, ethane C2H6, propane CH3H8, butane CH4H10, pentane CH5H12,
hexane CH6H14, heptane CH7H16, octane CH8H18, nonane CH9H20, decane CH10H22
Alkanes burn in oxygen to give carbon dioxide and water.
Candle wax is a mixture of different alkanes that are solid at room temperature.
Alkanes are usually associated with natural petroleum deposits and can be distilled from petroleum.
1. Alkanes (paraffins) are saturated hydrocarbons, i.e. all single bonds between C atoms, have formula CnH2n +2 and names end in "ane".
The names of unbranched alkanes come from the number of carbon atoms.
The name of branched alkanes come from the longest chain of carbon atoms.
The hydrocarbon branches, alkyl groups, symbol R, are formed by removing one hydrogen atom from the alkane,
and named by changing the "ane" to "yl", e.g. methane, CH4 to methyl, CH3 - , also "Me".
The carbon atoms of the longest continuous name are numbered starting at the end of the chain closest to the first branch.
An eight carbon chain with an ethyl group attached toCarbon 5, and a methyl group attached toCarbon 3 and carbon 4, is called 5-ethyl-3, 4-dimethyloctane.
Saturated hydrocarbons, e.g. hexane C6H14, all carbons have either four or three hydrogens bonded to them and no double bonds, triple bonds or rings.
They react in almost the same way.
Formation of alkanes:
* Hydrogenation of alkenes --> alkanes
CH2=CH2 + H2 --> CH3-CH3 (Pt catalyst)
ethylene + hydrogen --> ethane
CH3CH=CHCH3 + H2 --> CH3CH2CH2CH3 (Pt catalyst)
* Decarboxylation (remove CO2) from molecules that have -COOH group
RCOONa + NaOH --> R-H + Na2CO3 (dry distillation with soda lime)
CH3COONa + NaOH --> CH4 + Na2CO3 16.3.3 Friedel-Crafts reaction
The reaction substitutes a hydrogen atom in an arene ring of a halogen alkane by an organic group, R, using aluminium chloride catalyst.
RCl + AlCl3 --> R + + AlCl4 -
For example, benzene with chloromethane forms methyl benzene.
benzene + CH3 + --> benzene-CH3 + H +
CH3Cl +AlCl3 --> CH3 + +AlCl4 - 16.3.5 Oximes
Oximes (hydrox-imino-alkanes), R1R2C=NOH, where R1= organic side chain and if R2 = hydrogen, aldoxime forms or if R2 = organic group, ketoxime forms.
(-CNOH group) (ketone or aldehyde + hydroxylamine - water) (RCNOHR'), e.g. ethanal oxime (acetaldehyde oxime, AAO), CH3CH=NOH 16.4.1Alkenes CnH2n, olefins
Alkenes (olefins): aliphatic hydrocarbons that contain one or more double bonds, i.e. dienes.
Alkene, R1R2C=CR3R4, (double CC bond =, Prefix: alkenyl-, Suffix: -ene (no principal functional group)
Alkene (olefins, olefines), CnH2n, e.g. ethylene, ethene C2H4, ethene (ethylene) H2C=CH2, amylene, propadiene (allene)
R2C=C=CR2, dienes buta-1.2-diene, CH3CH=C=CH2, amylene See diagram 16.1.1: Cyclodienes, cis-trans alkenes.
1. Suffix: -ene for C=C (olefin, olefins, olefines) are unsaturated hydrocarbons with at least one double bond between C atoms, C=C.
Alkenes have the formula CnH2n, and include: ethene (ethylene, C2H4, CH2=CH2, ethenyl (vinyl CH2=CH-),
3-propenyl (allyl, CH2=CH-CH2-, e.g. vinyl chloride, (chlorethene, CH2CHCl), allyl chloride (3-chloropropene CH2=CH-CH2Cl).
(In the textile trade, "olefin" refers to synthetic fibre, polyolefin fibre, that are long-chain polymers of ethylene or propylene, i.e. polyethylene (polypropylene, PP).
Alkenes decolorize acidified potassium permanganate solution and bromine solution.
2. The cycloalkenes, cycloolefins, are closed chain, non-aromatic forms, e.g. cyclopropene CH.CH.CH2, cyclobutene, cyclopentene, cyclohexene. 16.4.2 Ethene
Ethylene (IUPAC name: ethene), hydrocarbon, formula C2H4 or H2C=CH2. 13.3.0: Prepare gases with gas generation apparatus
The preparation is an example of the dehydration of an alcohol.
1. Slowly add 10 mL of concentrated sulfuric acid to 5 mL of ethanol and 1 g of powdered aluminium sulfate in the gas preparation apparatus. Be careful!
Pass the gas formed through sodium hydroxide solution to remove sulfur dioxide and carbon dioxide!.
Collect the gas over water.
Heat only if necessary.
Pass the gas through sulfuric acid as dehydrating agent.
CH3CH2OH --> H2C=CH2 + H2O 16.4.3 Prepare ethene
1. Add 3 mL ethanol to a plug of glass wool in a boiling tube.
Glass wool is not recommended for use in school laboratories.
Cover the glass wool with porous pot and heat the porous pot.
C2H5OH --> C2H4 (g) + H2O
2. This experiment was called the "wet asbestos method", because asbestos wool was used to soak up the ethyl iodide in the test-tube.
However, asbestos wool is not allowed in schools.
Pour 2 cm methyl iodide in a test-tube.
Add 5 g of copper turnings and push it down firmly with a spatula.
Set up the apparatus and heat the mixture.
2CH3I + 2Cu --> C2H6 + Cu2I2
3. Prepare ethene with ethanol, method 1.
Put some cleaned and dried unglazed porcelain chips in a flask.
Add 10 mL of pure ethanol (absolute alcohol).
Slowly pour 30 mL of concentrated sulfuric acid down the sides of the flask. Be careful!.
Shake the flask gently under cool water to avoid alcohol being carbonized, because of increase in temperature.
Fit the flask with a thermometer and a delivery tube inserted in a two-holes rubber stopper.
Heat the flask to raise the temperature quickly to 170 oC, then control at 170 oC.
This heating procedure is used to increase the use ratio of ethanol and decrease by-products.
Wait until exclusion of the air in the flask and then collect the produced ethene gas over water.
Concentrated sulfuric acid and sodium hydroxide solution can be used to absorb and remove ethyl ether vapour, carbon dioxide and sulfur dioxide in the ethene.
C2H5OH (l) --> C2H4 (g) + H2O at 170 oC
4. Prepare ethene with ethanol, method 2. See diagram 16.10.3 : Prepare ethene.
Absorb ethanol in cotton wool and push this to the bottom of a hard glass test-tube.
Pack small pieces of unglazed porcelain in the middle of the test-tube.
Fit a delivery tube toCollect ethene gas over water.
First heat the porous pot strongly and then heat gently the cotton wool to produce some ethanol vapour.
This vapour breaks down over the hot porous pot to produce ethene gas and water vapour.
The temperature should be above 170 oC, otherwise the reaction produces dimethyl ether.
Collect the ethene over water.
Be careful! Disconnect the delivery tube when heating stops to avoid a "suck back" of water onto the hot porous pot. 16.4.4 Dienes, diolefins
Dienes are alkenes with twoC double bonds in the molecule, CnH2n-2, (same formula as alkynes, so dienes are alkyne isomers).
Cumulated dienes have twoC double bonds next to each other, e.g. 1,2-propadiene, H2C=C=CH2.
Conjugated dienes have two double bonds separated by a single bond, e.g. (buta-1,3-diene), CH2=CH-CH=CH2 and (1,3-pentadiene) H2C=CH-CH=CH-CH3.
Unconjugated dienes, have two double bonds separated by two or more single bonds.
Cyclodienes, 1.3-cyclohexadiene, 1.4-cyclohexadiene 16.5.0 Aromatic hydrocarbons, Arenes See diagram 16.8.1: Benzene compounds Benzene, C6H6, has a stable six-sided ring structure.
Arenes, aromatic hydrocarbons, are cyclic unsaturated compounds, the simplest being benzene, C6H6.
Arenes, e.g. benzene, naphthalene, anthracene, phenanthrene
Arenes do not mix with water, but they do mix with hydrocarbons and all non-polar solvents.
Arenes usually burn with a smoky flame, as do most aromatic compounds, because of the high carbon: nitrogen ratio.
So when they burn in air, some carbon soot usually remains in the air.
Arenes are called aromatic compounds, because the first arenes were isolated from fragrant oils.
However, nowadays aromatic refers to the structure, not the smell.
Nitration of benzene. See 10.01.10: Liebig condenser
Heat benzene with a mixture of concentrated nitric acid and concentrated sulfuric acid, (the catalyst) in a Liebig condenser at 330 K.
C6H6 + HNO3 --> C6H5NO2 + H2O (1) 16.6.1.0 Ethane, C2H6, CH3CH3 13.3.0: Prepare gases with gas generation apparatus See diagram 16.1.1: Ethane
Ethane is a colourless and odourless gas, which has properties similar to methane. 16.6.1.1 Prepare ethane
This experiment was called the "wet asbestos method", because asbestos wool was used to soak up methyl iodide in the test-tube.
However, asbestos wool is not allowed in schools.
Pour 2 cm methyl iodide in a test-tube.
Add 5 g of copper turnings and push it down firmly with a spatula.
Set up the apparatus and heat the mixture.
2CH3I + 2Cu --> C2H6 + Cu2I2 16.6.2.0, Propane, C3H8
Propane is a colourless liquefied petroleum gas, a bottled gas, BP -42.2 oC, catalytic cracking forms propylene, propellant, aerator
It is used as a fuel for gas barbecue and blow torch 16.6.4.0, Butane, C4H10
| See diagram 3.32: Collect insoluble gases over water, See 3.
| See diagram 16.1.2: Butane isomers.
Butane, n-Butane, BP -0.5 oC, RD 0.60 at 0 oC, is stored as liquid under pressure in steel cylinders.
Butane is Calor gas and cigarette lighter gas, used in cigarette lighters and portable gas appliances.
Butane is a Highly flammable gas at room temperature, vapour pressure 2.4 atm.
Butane gas is stored as liquid under pressure in fire lighters.
If lighter trigger is squeezed, canister opens and liquid forms a vapour.
Cigarette lighter fuel is 90% butane, isomer isobutane.
Sudden decompression in aircraft can cause butane cannisters to rupture. 16.6.4.1, Prepare butane 13.3.0: Prepare gases with gas generation apparatus
This experiment was called the "wet asbestos method", because asbestos wool was used to soak up the ethyl iodide in the test-tube.
However, asbestos wool is not allowed in schools.
Pour 2 cm ethyl iodide in a test-tube.
Add 5 g of copper turnings and push it down firmly with a spatula.
Set up the gas generation apparatus and heat the mixture.
2C2H5I + 2Cu --> C4H10 + Cu2I2
Combustion of butane
Butane / Oxygen combustion
2C4H10 + 13O2 --> 8CO2 + 10H2O + energy 16.6.5.0 Pentane, C5H12
Pentane, BP 36.3 oC, RD 0.63, is made by distillation of petroleum. 16.6.6.0 Hexane, C6H14
Hexane, BP 68.7 oC, RD 0.66, exists as five compounds with same formula, normal hexane, n-hexane, in petrol and petroleum ether solvent.
It is a colourless liquid, with an ethereal odour.
"Shellite" (Australia) is 60% hexane and 40% heptane. 16.6.7.0 Heptane, C7H16
Heptane, BP 98 oC, RD 0.68, nine isomers, normal heptane has similar properties to normal hexane. 16.7.9 Octane number
Octane is in some hydrocarbons with unbranched carbon chains, which prematurely explode in the cylinder.
They produce an audible knocking sound or "ping" sound (knocking, pinking).
A scale of "knock property" has isooctane (2,2,4-trimethylpentane) at 100 (a good fuel) and heptane at 0 (a poor fuel).
So gasoline with octane number 80 has the same properties as a mixture of 80% isooctane and 29% heptane.
Octane number is the percentage of iso-octane normal heptane mix with the same knocking behaviour of the fuel being tested, so it indicates the knock rating of a motor fuel.
A high octane fuel has a longer self-ignition delay in motor car engine.
In Brisbane, most "family cars" use 91 octane "unleaded petrol".
This is the lowest octane rating of the different petrol sold in garages.
A high octane rating of a fuel means that it has less tendency to pre-ignite in a high compression engine.
Pre-ignition means that before the spark plug has fired, the fuel air mixture burns, because of heat created in the cylinder by compression.
Unleaded petrol has the octane rating 98.
Table 16.1.1h
Engine compression ratio
4: 1
5: 1
6: 1
7: 1
8: 1
9: 1
10: 1
11: 1
12: 1
Octane number to be knock-free
60
73
81
87
91
95
98
100
102
16.1.2.3 Trienes
Trienes are alkenes with has three C double bonds, e.g. C6H8, (1,3,5-hexatriene). Menthatriene, C10H14, p-Mentha-1,3,8-triene, para-menthatriene, terpene, camphor, woody aroma and taste.
It is not used for fragrances of flavours, colourless-yellow liquid, roasted odour, parsley aroma.
It occurs in Parsley, (Petroselinium crispum), Apiaceae, and in Jesuit's tea, (Dysphania ambrosioides), Amaranthaceae 16.6.1 Alcohols See diagram 16.0.1: Tetrahedral geometry of carbon, methane molecule, isobutyl alcohol
Alcohols, CnH2n+1OH, (ROH), (-ol), alkanols, the two simplest alkanols are methanol CH3OH, and ethanol C2H5OH.
The R in an alcohol formula is not specific. Alkanol, a type of alcohol ROH, but R must be an alkane molecule.
Alkanol, aliphatic alcohol, alkyl alcohol, ROH (Prefix: hydroxy-), (Suffix: -ol) (-OH: alcohol)
Alcohols are organic compounds with the functional group -OH, but when -OH attached to an aromatic ring called phenols.
Alcohols, alcohols group: (-OH) Suffix: (ol)
Primary alcohols
Methanol, CH3OH Butyl alcohol, butanol C4H9OH, 1-butanol, butan-1-ol, n-butyl alcohol, paint solvent, in hydraulic brake fluids
Secondary alcohols
propan-2-ol (CH3)2CHOH
2-butanol, butan-2-ol, sec-butanol, sec-butyl alcohol, CH3CHOHCH2CH3
Tertiary alcohols
tert butanol, tert-butyl alcohol, (2-methylpropan-2-ol), (CH3)3COH, CH3CH3COHCH3, simplest tertiary alcohol
Alcohols, R-OH, are compounds in which a functional group, the hydroxyl group, -OH, is attached to a saturated carbon atom, e.g. R3COH.
The "hydroxyl" refers to the radical HO - .
The "alcohol" in alcoholic beverages is ethanol, ethyl alcohol, CH3CH2OH.
Alkanol, CnH2n+2O 16.6.2 Alcohols, primary, secondary and tertiary aliphatic alcohols
Primary alcohols RCH2OH, Secondary alcohols R2CHOH, Tertiary alcohols R3COH
Carbon dioxide and fermentation for brewing:
Rubbing alcohol: , surgical spirit.
Tests for alcohols:
Primary alcohols:
Primary alcohols, e.g. methanol (methyl alcohol, CH3OH, propanol, (isomer propan-1-ol, n-propyl alcohol, CH3CH2CH2OH, and butan-1-ol (1-butanol, n-butanol, CH3(CH2)3OH, have two hydrogen atoms attached to the carbon atom attached to the hydroxyl group (-OH).
So they all have -CH2OH in their molecules.
They can be directly oxidized to aldehydes or carboxylic acids using oxidizing agents.
(O)R1-CH(OH)-R2 --> R1-C(O)-R2(O)R-CH2OH --> R-CHO(O)R-CHO --> R-COOH
Allyl alcohol C3H6O, CH2CHCH2OH, prop-2-en-1-ol, 2-propen-1-ol, Highly toxic by all routes
Secondary alcohols:
Secondary alcohols, e.g. propan-2-ol (CH3)2CHOH, rubbing alcohol, isopropyl alcohol and secondary butyl alcohol, butan-2-ol CH3CH2CH(CH3)OH, or CH3CH(OH)C2H5, have one hydrogen atom attached to the carbon atom attached to the hydroxyl group (-OH).
So they all have (-CHOH), in their molecules.
They can be slowly oxidized to ketones.
(O)R1-CH(OH)-R2 --> R1-C(O)-R2 Isopropanol, isopropyl alcohol
Tertiary alcohols:
Tertiary alcohols, e.g. 2-methylpropan-2-ol, 2-methyl-2-propanol (CH3)3COH, tertiary butyl alcohol has no hydrogen atom attached to the carbon atom attached to the
-OH group.
So they all have -COH in their molecules. 16.6.3 Butanol. C4H9OH
"Butanol" butyl alcohol C4H9OH has 4 isomers: 1. n-butanol (1-butanol), 2. sec-butanol (2-butanol), 3.isobutanol (2-methylpropan-1-ol), 4. tert-butanol (2-methylpropanol).
1. Butan-1-ol, n-butanol, 1-butanol, n-butyl alcohol, butyl alcohol, primary alcohol), C4H9OH, n-propyl carbinol, (biobutanol), colourless liquid used in paint solvent, in hydraulic brake fluids, in organic chemical synthesis, plasticizers, detergents
2. Butan-2-ol, sec-butanol, 2-butanol, sec-butyl alcohol (secondary alcohol), C4H10O, secondary butanol, secondary butyl alcohol, s-butyl alcohol, product of grain and hops fermentation
3. Isobutanol, isobutyl alcohol, IBA, C4H10O, 2-methylpropan-1-ol, 2-methyl-1-propanol, additive to reduce viscosity, flavouring agent
4. Tert-butanol, t-butanol, tert-butyl alcohol,(TBA) (CH3)3COH, 2-methypropan-2-ol, 2-methyl-1-propanol, trimethyl carbinol
It is the simplest tertiary alcohol, so is often just called "butyl alcohol" or "butanol".
It has the hydroxyl on the same carbon with three methyl groups, used as a paint remover and solvent, Harmful by all routes, flammable. 16.6.4 Butyl glycol
Butyl glycol C4H9OCH2CH2OH, 2-butoxyethanol, butyl cellosolve, butyl ether of ethylene glycol, in window cleaner "Windex", in inks, in paint, in solvents 16.6.5 Dihydric alcohols, glycols
Dihydric alcohols, glycols, diols, have two hydroxyl groups on different carbon atoms, e.g.:.
1.Ethane-1,2-diol, ethylene glycol, ethanediol, "glycol", 1.2-dihydroxyethane
(C2H4O)nH2O, CH2OHCH2OH, BP 197.5 oC, car radiator antifreeze, coolant, in hydraulic fluids, paint and plastic solvent, sweet taste, but poisonous
2. Butane-1,4-diol, C4H10O2, HO(CH2]4OH, tetramethylene glycol
CH2CH2 (oxidation) --> CH2OCH2 (+ water) --> HOCH2CH2CH2CH2OH
ethene (oxidation) --> epoxyethane (+ water) --> ethane-1,2-diol (glycol, antifreeze)
3. Propane-1,2 diol, propylene glycol, C3H8O2, CH3CHOHCH2OH, colourless, tasteless, odourless, solvent for pharmaceuticals 16.6.6 Ethanol
Ethanol, ACS reagent, 99.5% (200 proof), absolute, ethyl alcohol, CH3CH2OH, C2H5OH, clear, colourless, mobile liquid, volatile organic compound, inflammable.
It has a pleasant odour, burning taste, miscible with water and most organic solvents, rectified spirit, grain alcohol, spirit of wine.
Constant boiling mixture = 95.6% ethanol and 4.4% water, BP. -78.3 oC, absolute alcohol = 100% ethanol.
RD 0.79 gm cm -3 , BP. 78.5 oC, absorbs moisture from air.
Ethyl alcohol becomes very viscous at liquid nitrogen temperatures.
This is known as 'foetal alcohol syndrome'.
Consumption of ethanol during pregnancy may affect the unborn child, resulting in abortion, developmental problems, or birth defects, "foetal alcohol syndrome".
Chronic ingestion of ethanol may cause liver cirrhosis and affect the nervous system.
Ethanol safety
Do not heat ethanol over an open flame, but use a water bath.
Ethanol may be used in small quantities in alcohol burners to measure heat of combustion and for reaction with alkanoic acids to form esters.
Ethanol forms violently explosive mixtures with nitric acid and other oxidizing agents.
Ethanol with acidified dichromate solutions is highly exothermic.
Ethanol reacts violently with potassium. 16.6.7 Fatty alcohols
Fatty alcohols are aliphatic alcohols from natural fats and oils in plants and animals.
They have an even number of carbon atoms.
The -OH group is attached to the terminal carbon.
They are amphipatic (having both polar (water-soluble) and nonpolar (not water-soluble) portions in the structure of the molecule,
so they can act as non-ionic surfactants.
Fatty alcohols are used in cosmetic formulations as emulsifiers, emollients and thickeners.
List of some fatty alcohols: Butyl alcohol, C4H10O Isoamyl alcohol, C5H12O
Capryl alcohol, 1-octanol, C8H18O, clear colourless liquid, aromatic odour, insoluble in water, floats on water, irritate eyes, nose.
Capric alcohol, 1-decanol, C10H22O, clear colourless liquid, sweet fat-like odour, insoluble in water.
Lauryl alcohol, 1-dodecanol), C12H26O, from coconut oil fatty acids, is tasteless and colourless, but has a flowery smell. Cetyl alcohol, C16H34O
Cetostearyl alcohol, C34H72O2, waxy white solid, soapy odour, floats on water.
Stearyl alcohol, C18H38O : 16.6.8.1
Behenyl alcohol, C22H46O, 1-docosanol, alcohol, aliphatic alcohol, antiviral activity, topical treatment of recurrent herpes simplex (cold sores)
Ceryl alcohol, 1-hexacosanol, C26H54O, very long-chain primary fatty alcohol
Heptacosanol, 1-heptacosanol, C27H56O, very long-chain primary fatty alcohol
It occurs in Euphorbia granulata, and Sigesbeckia glabrescens. 16.6.8H Methylated spirits
Methylated spirits (95% CH3CH2OH, 5% CH3OH), or absolute ethanol is usually denaturated with 4.8% methanol.
However, thet composition is legally different in different countries, e.g. Australia 2% methanol.
Methylated spirits, methylated ethanol, "spirits", "metho".
Methylated spirits is sold retail in Australia as 95% ethanol, UN 1170, duplicator fluid / duplicator spirit, Fordigraph spirit duplicator fluid
Denatured alcohol
Additional substances are used to "denature" the ethanol so it cannot be consumed
However, it may be consumed by Aboriginal people in Australia by mixing methylated spirits with condensed milk.
The sugar derivative, sucrose octoacetate, in Thaumatin, from the West African plant Ketemfe (Thaumatococcus danielli), E 957, relative sweetness 750 to 1 600
It is bitter to raste and is used as a harmless denaturant for alcohol to make denatured spirit undrinkable.
Previously, denatured spirit contained methanol to make it undrinkable, but it caused blindness in alcoholics determined to drink it.
Use of methanol in home-made alcoholic beverages is illegal, because it may cause blindness.
Spirit vini meth (90% ethanol + 5% v/v methanol+ 5% water)
Denatured alcohol, denatured spirits (+ 2% of methyl alcohol, pyridine + other coal tar unpalatable chemicals).
(in UK ethanol + 9.5% methanol + 0.5% pyridine + blue dye), (190-proof ethanol + 4% methanol + 1% other denaturants), (99% methylated spirits +1% bitrex)
Consumption of methylated spirits
Do not consume methylated spirits.
If methylated spirits is swallowed, do NOT induce vomiting, because it may enter the lungs.
Flammability of methylated spirits
Methylated spirit is highly flammable and must not be used near naked flames.
It must be boiled in a beaker or set on wire gauze over a Bunsen burner to extract chlorophyll from leaves.
Do not heat methylated spirit over a Bunsen burner, even in a closed container such as a flask with a reflux condenser, because the flask may crack.
Methylated spirit burns with a nearly colourless flame, so if there is a fire, be careful of the invisible flames.
Use a carbon dioxide fire extinguisher and fire blankets to smother the flames.
Heating methylated spirits
Use a water bath to heat methylated spirit in a flask, so if the flask cracks, a mixture of water and methylated spirit is less flammable than pure methylated spirit.
Handling methylated spirits
Repeated contact of the skin with methylated spirit can cause dermatitis, so wear rubber gloves if using methylated spirit as a solvent for cleaning.
Mixing methylated spirits
Do not mix methylated spirit with an oxidizing acid, e.g. concentrated nitric acid, because a vigorous reaction or explosion may occur.
Uses of methylated spirits
Use methylated spirit as a cheap low toxicity cleaning solvent for solvent extraction.
Observe the rapid changes in colour during the dissolution of plant pigments in methylated spirits. 16.6.10 Nitroglycerine
Nitroglycerine (UK), Nitroglycerin (USA), C3H5N3O9, ester of nitric acid
glycerol + cold mixture of concentrated sulfuric acid + nitric acid --> C3H5N3O9
Nitroglycerine is a colourless, insoluble oil, solidifies on cooling, contact explosive, used to make dynamite and cordite.
Dynamite is nitroglycerine surrounded by a ring of diatomite, diatomaceous earth, kieselgur, SiO2Al2O3Fe2O3.
Cordite is a smokeless explosive powder, shaped as cords, e.g. gun cotton + nitroglycerine + petroleum jelly.
Nitroglycerine is a very unstable liquid that explodes if given a slight shock.
It freezes at 13 oC, but is more likely to explode if solid.
It is used to make safer explosives, e.g. dynamite.
It is also used in very small tablets for the heart condition angina pectoris where people get out of breath and suffer pain in the chest from over-exertion. 16.6.11 Nitrocellulose, gun cotton
Nitrocellulose is too dangerous to be used in schools.
Potassium nitrate is dissolved in concentrated sulfuric acid to produce a dangerous vapour, then cooled in an ice and salt mixture, then cotton balls are added.
Later more sulfuric acid is added, then the cotton balls are removed and placed in sodium bicarbonate solution until no more bubbles form, then dried. 16.6.12 Phenols
Phenols, group: (OH-C), in a benzene ring, Phenol = C6H5O6 See diagram 16.1.4.3: Phenols, quinones, naphthols, coniferyl alcohol (p-coumaryl alcohol), urushiol, organohalogens.
1. Phenols, Ar-OH, are compounds with an hydroxyl group, -OH, is firmly attached to an aromatic ring, e.g. benzene, 2-naphthol, benzene-OH, hydroxybenzenes.
Phenols, group: (OH-C), in a benzene ring, Phenol = C6H5O6: 16.6.12
Phenols (hydroxyl group -OH), connected to a carbon atom in a benzene ring, benzene-OH, hydroxybenzenes.
The -OH is so firmly attached that the O-H bond tends to break to lose an H + ion to form a weak acid.
2. Phenols divided into mono-, di-, tri- tetra-, and polyhydric phenols, e.g. p-chlorophenol C6H4ClOH, 2,4,6-tribromophenol, C6H2Br3OH.
Chlorophenol red, C19H12Cl2O5S, (acid-base indicator):
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PLA synthetic fibre, polylactic acid, polylactide 9.6.5 Vitamin E 9.6.6 Antioxidants, vitamin E 9.6.7 Free radicals and antioxidants 3.9.1: Cholesterol C27H46O 16.6.13 Propanol, C3H7OH
Propanol C3H7OH has two isomers:.
1. 1-propanol (n-propyl alcohol) C3H8O, CH3CH2CH2OH, Highly flammable, Toxic if ingested
2. 2-propanol (iso-propyl alcohol) C3H8O, CH3CH(OH)CH3, C3H7OH, sec-propyl alcohol, rubbing alcohol, Flammable
Potassium dichromate as an oxidizing agent:.
propan-2-ol + potassium dichromate (VI) solution + dilute sulfuric acid --> water + propanone (acetone) ketone
CH3CHOHCH + O (from oxidizing agent) --> (CH3)2CO + H2O 16.6.14 Pyrogallol
Pyrogallol, (1,2,3-trihydroxybenzene), C6H6O3, C6H3(OH)3, white crystals, reducing agent
It reacts with oxygen in the air to form a brown polymer.
It is used where oxygen must be eliminated from a gas or from the air.
It is highly toxic if ingested, and corrosive to skin.
Pyrogallol is prepared by heating Gallic acid.
Germination and air, germination and the need for oxygen: 9.4.9.
Tests for gas collected in a respirometer: 9.1.19.
Poisons, First Aid: 3.10.0 16.6.15 Resorcinol See diagram 1.3.2.3: Resorcinol.
Resorcinol. C6H4(OH)2, (benzene-1,3-diol) is a dihydric phenol used with formaldehyde (methanal, HCHO).
Resorcinol, crystals, resorcin, m-dihydroxybenzene, 1.3-dihydroxybenzene, benzene-1-3-diol, benzene-1-3-diol, 1.3 benzenediol (a dihydroxy phenol).
Resorcinol is harmful, corrosive to skin.
Resorcinol, Solution <10%, Not hazardous, but do not ingest.
Resorcinol (test reagent in ethanol), explosive with nitric acid, turns red in light, antiseptic, colourless crystals, used for cold-setting adhesives with formaldehyde, also used to make plasticizers, resins and fluorescein dyes.
Resorcinol C6H6O2, argan oil, in Argania spinosa.
Prepare formaldehyde resorcinol resin: 3.4.6.1.
Resorcinol, Xanthene dyes: 7.9.56.1. 16.6.16 Prepare sodium ethoxide
Sodium ethoxide is the salt of a weak acid, ethanoic acid, and a strong base, sodium hydroxide.
Add a pinhead size piece of sodium to 1 mL of ethyl alcohol. 16.6.17 Triclosan See diagram 1.3.2.3: Triclosan.
Triclosan, TCS, 5-chloro-2-(2,4-dichlorophenoxy) phenol, C12H7Cl3O2, is an organohalogen polychlorophenoxy phenol used in anti-bacterial and anti-fungal products, and in low concentrations in many other products, including toothpaste, mouthwash, deodorants, soap, scent, detergent dishwashing liquid, hand washes, at high concentrations is harmful by inhalation, irritant, environmental danger.
Triclosan is suspected of causing bacterial resistance, because of it widespread use and occurrence in the environment and may weaken the immune system.
Other organohalogens include: 2,4 6-trichlorophenol, 2,4,6-tribromianisole, 2,4,6-trichloroanisole.
chlorophenol compounds + filamentous fungi --> 2,4,6-trichloroanisole. 16.6.18 Trihydric alcohols, glycerol
Trihydric alcohols, have three hydroxyl groups on different carbon atoms, e.g. glycerol C3H8O3. 16.9.1 Allyl mercaptan
Allyl mercaptan, flavouring agent, 2-propene-1-thiol, from garlic, C3H6S, EC Number (EINECS): 870-23-5.
Odour threshold value: 6 × 10 7 molecules / mL of air. 16.9.2 Ethyl mercaptan
Ethyl mercaptan, ethanethiol, CH3CH2SH, colourless gas, offensive rotten cabbage smell, poisonous and used as oderant in LPG gas at less than poisonous concentration to allow early detection of gas leaks.
There is some evidence that very old men cannot smell it and so are susceptible to LPG gas poisoning. 16.9.3 Methyl mercaptan
Methyl mercaptan, methanethiol, methyl mercaptan, "captan", CH3SH, CH4S, (MeSH), simplest thiol, an alkanethiol, colourless gas, low-boiling liquid, denser than water, very toxic by inhalation, can be absorbed through the skin, highly flammable, liquid burns causes frostbite
It has a sharp putrid odour, but the sense of smell cannot be relied upon to warn of the presence of vapours at low concentrations, odour threshold 0.002 ppm
It comes from from decayed organic matter, pulp mills, oil refineries;
It has an offensive rotten cabbage or decomposing vegetables smell, as in bad breath and flatus.
It occurs in some nuts and cheese, in blood, brain, and other tissues of people and animals.
It is released from animal faeces released from decaying organic matter in marshes and as decay product of wood in pulp mills.
It occurs in the natural gas of certain regions, in coal tar, in some crude oils, and is manufactured for plastics industry, pesticides, jet fuel additive. 16.9.4 Thiols (Mercaptans) See diagram 16.1.4.3 : Thiophenol (phenyl mercaptan) See diagram 16.1.4.3 : Thiophenol (phenyl mercaptan)
See diagram 16.13.10: Thiols, Metam, zineb.
Thiols (mercaptans), thio alcohols, Thioalcohols group: (-SH), Suffix: (-thiol) (SH in an organic compound).
Thiols, thio-alcohols (RSH, R not equal to H) (sulfhydryl group: -SH, characteristic of thiols).
(Suffix: -thiol), [old name: mercaptans, because react with mercuric ion to produce mercaptides (RS)2Hg, e.g. methanethiol, methyl mercaptan CH3SH, ethanethiol MeCH2SH,
Thiols, RS-H, are oxidized to disulfides, RS-SR. 16.1.5.5 Acyl halide
Acyl halide, acid chloride, Acid chlorides group: (-COCL), Suffix: -oyl chloride.
Acyl chloride (RCOCl), e.g. ethanoyl chloride (Acetyl chloride, CH3COCl). 16.1.5.6 Amides
Amides, acid amides (-amide) (amide group: -CONH2, RCONH2
Suffix: -amide, e.g. urea, H2NC=ONH2
[IUPAC says: Do NOT distinguish amides with NH2, NHR, NR2 groups by the terms "primary, secondary, tertiary".]
1. Primary amides RCONH2, e.g. alkanamides: ethanamide (acetamide), CH3CONH2 propanamide C2H5CONH2.
2. Secondary amides, N-substituted amides RCONHR'.
3. Tertiary amides RCNR'R".
Secondary or tertiary amides have the prefix N, e.g. N-ethylethanamide, CH3CONHCH2CH3, N.N-dimethylmethanamide HCON(CH3)2
(the polymer group -CO-NH-)
inorganic amides, e.g. KNH2. 16.1.5.6a Carbamates See diagram 16.13.7: Carbamates, carbaryl, methiocarb.
Carbamate ion, CH2NO2-, is a derivatives of carbamic acid, NH2COOH, H2NC(=O)OH
Carbamates are esters of carbamic acid, CH2NO2-, NH2COOH,
Carbamate esters are called urethanes.
A urethane, C3H7NO2, NH2COOC2H5 is the ethyl ester of carbamic acid and is found in alcoholic beverages
ethanol + carbamic acid --> urethane
Urethanes are esters of carbamic acid, i.e. alkyl carbamates.
Polymers that include repeating carbamate units, -NH (CO)O-. are called polyurethanes
Polyurethanes are from the polymerization of isocyanates.
Examples of carbamates: carbamic acid, ammonium carbamate, bendiocarb, carbaryl, urethane.
Combustion of carbamates may produce noxious NOx and carbon monoxide.
Carbamates are more reactive than amides and can form polyurethane resins.
Carbamates are incompatible with strong acids and bases, strong oxidizing acids, and peroxides.
Many carbamates are used as pesticides for their anticholinesterase activity, e.g. carbaryl, propoxur, bendiocarb and methomyl.
Carbamates, carbamate R-O (C=O)N-R,R, 16.1.5.6a See diagram 16.13.7 Carbamates, carbaryl, methiocarb See diagram 16.13.8 Deet, DMP dimethylphthalate
Amides, 16.1.5.6
Ammonium carbonate, smelling salts, 12.16.3.5
Carbamide (urea), CO(NH2)2, CO(NH2)2
Carbazole C12H9N
Deet, N,N-Diethyl-meta-toluamide, C12H17NO
Ethyl carbamate, C3H7NO2, blood flow in a fish, 9.217
Ethyl carbamate, Urethane, carbamate esters, 7.9.54.2
Mancozeb (fungicide), 4.6.14
Maneb (fungicide), 4.6.13
Organophosphate and carbamate insecticides, 4.5b Organophosphate and carbamate insecticides
Thiocarbamate R-O (C=S)N-R, R Urea CO(NH2)2 Urethane carbamate esters = urethanes, R2NC(=O)OR', where R' not = H, R= ethyl 16.1.5.6.1 Acrylamide
Acrylamide, C3H5NO, 2-propenamide, ethylene carboxamide, acrylic amide, propenoic acid, UN 2074, vinyl amide, is toxic if ingested, crystalline form and aqueous solutions, monomer or polymer.
Acrylamide, C3H5NO, CH2CHCONH2, is the amide of acrylic acid, propenoic acid CH2CHCOOH, an unsaturated liquid carboxylic acid.
Acrylamide is a poison, harmful if swallowed, inhaled or absorbed through skin, affects central and peripheral nervous systems and reproductive system.
It causes irritation to skin, eyes and respiratory tract, suspected cancer hazard depending on level and duration of exposure, possible birth defect hazard.
It is thermally unstable, but can polymerize explosively if heated to the melting point.
It is most common in overcooked French fries and potatoChips, also burned toast and burned high carbohydrate foods.
The European Food Safety Authority (EFSA) recommends consuming golden not dark brown or black toast, short espresso not lungo, and not overcooked foods.
Acrylamide is a toxic chemical which could cause tumours.
It is not deliberately added to food by manufacturers, it is a by-product of the cooking process and has always been around.
A lot of research has been done into the chemical's effect on humans, first highlighted as a potential risk in a 2002 Swedish study.
In 2015, the European Food Standard Agency (EFSA) published its first full risk assessment of acrylamide in food, which found that the chemical potentially increases the risk of cancer for all age groups.
FSA: "This means that acrylamide might contribute to your lifetime risk of developing cancer, but it is not possible to estimate how big this contribution may be.
Eating too much processed and red meat, and cooking meat at high temperatures on grills and BBQs, could also increase your cancer risk.
"Coffee has been shown to be a healthy beverage." said William Murray, president the National Coffee Association, in reaction to the decision.
A previous case resulted in potato-chip makers agreeing in 2008 to pay $3 million and remove acrylamide from their products.
The chip-makers opted to do that rather than post cancer warnings like those that are found, and largely ignored, throughout California.
He argued the lawsuit "does nothing to improve public health.".
Kathryn M. Wilson, Harvard University, told the LA Times: "I think the evidence that acrylamide makes a difference for human cancer risk is pretty weak.".
31/3/2018 LOS ANGELES.
A Los Angeles judge determined that coffee companies must carry a cancer warning label, because of a chemical produced in the roasting process.
The judge said Wednesday that Starbucks and other companies failed to show that benefits from drinking coffee outweighed any risks.
He ruled in an earlier phase of trial that companies had not shown the threat from the chemical was insignificant.
The Council for Education and Research on Toxics, a nonprofit group, sued Starbucks and 90 other companies as follows:
Under a state law that requires warnings on a wide range of chemicals that can cause cancer, including acrylamide, a carcinogen present in coffee. 16.1.5.7 Acid anhydrides
Acid anhydrides, R1(C=O)O(C=O)R2
Ethanoic anhydride (acetic anhydride), (C4H6O3), (CH3CO)2O, (Ac2O) 16.1.13 Prepare triodomethane (iodoform)
Add five drops of iodine solution to five drops of ethanol.
Add drops of dilute sodium hydroxide solution until the brown colour of iodine disappears.
Observe the crystals under a microscope.
C2H5OH + 4I2 + 6NaOH --> HCOONa + 5NaI + 5H2O + CHI3.
ethanol + iodine + sodium hydroxide --> sodium methanoate (sodium formate) + sodium iodide + water + triodomethane (iodoform). 16.2.3.1 Carbides, C 4-
Carbide are binary compounds of:.
1. C + electropositive element, e.g. calcium carbide, CaC2.
2. C + heavy metal, for cutting tools, e.g. aluminium carbide, Al4C3, chromium carbide, Cr3C2, iron carbide Fe3C (cementite).
Tungsten carbide ("carbide", WC), is used for cutting tools, milling tools, abrasives, jewellery.
Iron carbide is formed with carbon monoxide when iron oxide is heated with charcoal.
3Fe2O3 +11C --> 2Fe3C + 9CO (g).
Types of carbides: Methanides
1. Methanides, e.g. aluminium carbide, Al4C3
Hydrocarbyl anions, methyl anion, conjugate base of methane.
Methanides + water --> methane.
Al4C3 + H2O --> Al(OH)3 + CH4
2. Acetylides, e.g. calcium carbide, CaC2
Acetylides, salts of acetylide anion, C2 2- , (percarbide).
Acetylides are formed by alkali metals, alkaline earth metals, lanthanoid metals, e.g. sodium carbide Na2C2,
lanthanum carbide LaC2, aluminium carbide Al4C3, iron carbide (cementite) Fe3C.
Acetylides (percarbides), C2 2- + water --> acetylene.
Sodium acetylide C2HNa, Copper (I) acetylide Cu2C2.
Calcium acetylide CaC2 is commonly called calcium carbide.
Calcium carbide CaC2 (calcium dicarbide, "carbide", calcium acetylide, acetylenogen, ethnide dicarbide, Toxic by all routes.
CaC2 + 2H2O --> C2H2 + Ca(OH)2.
calcium carbide + water --> acetylene + calcium hydroxide.
Covalent carbides:
Covalent carbides, Boron carbide B4C, very hard material, is used in armour.
Silicon carbide, SiC (carborundum), abrasive, moissanite synthetic gemstone, emery paper, sanding paper, sharpening stone, fine particles, Toxic by inhalation.
Sesquicarbides:
Sesquicarbides, e.g. magnesium carbide, Mg2C3
C3 4-
Mg2C3 + H2O --> Mg(OH)2 + C3H4
magnesium carbide + water --> magnesium hydroxide + propyne (methylacetylene, CH3C≡CH 16.2.4.3.0 Amines
Amines, aliphatic amines, RNH2 - , R = alkyl group), ionization reaction of methylamine.
Amines have lower boiling temperatures than alcohols.
Methylamine and ethylamine are gases at room temperature.
Longer chain amines are volatile liquids with rotten fishy smells characteristic of decomposing proteins.
Amines are bases, can accept a H + ion, soCan react with acids to form salts and lose the fishy smell.
1. Primary amines: R-NH2
NH2 - = amino group, e.g. methylamine CH3-NH2, ethylamine CH3CH2-NH2. Aniline, C6H5NH2, phenylamine
2. Secondary amines: R2-NH
NH = imino group, e.g. dimethylamine CH3)2NH.
3. Tertiary amines: R3-N.
N = nitrogen, e.g. Triethylamine, C6H15N Trimethylamine, C3H9N Physostigmine, C15H21N3O2, tertiary amine 16.2.4.3.05 Clenbuterol, C12H18Cl2N2O
Clenbuterol is a performancing-enhancing drug banned by the International Olympic Committee.
It has been illegally used to build skeletal muscle and increase metabolism, but may cause heart attacks.
It has been used with beta-2 adrenomimetic properties at very low doses, as a bronchodilator in asthma treatment.
It is approved for use in some countries, but as at 2006, not an ingredient of any therapeutic drug approved by the USFDA. 16.2.4.3.1 Ethylenediamine
Ethylenediamine, C2H4(NH2)2, C2H8N2, H2NCH2CH2NH2, (1,2-diaminoethane), ligand, chelating agent, toxic by all routes, corrosive
Ethylenediamine, 1,2-diaminoethane, Solution < 1% Not hazardous
It is a clear colourless liquid, smells like ammonia, corrosive to tissue and produces toxic oxides of nitrogen during combustion.
It is used in large quantities to make many other chemicals and pharmacological excipients
ClCH2CH2Cl + 4 NH3 --> H2NCH2CH2NH2 + 2 NH4Cl.
1,2-dichloroethane + ammonia --> ethylenediamine + ammonium chloride. 16.2.4.7 Cyanocrylates
Cyanocrylates (CH2)C(CN)COOR, e.g. "Superglue": Me or Et ester
Ethyl cyanoacrylate, "Superglue", BE CAREFUL! Do not squirt in the eye! Toxic by all routes
Chemical suppliers: Ethyl 2-cyanoacrylate, liquid, C6H7NO2
GBL, γ-butyrolactone is a naturally occurring colourless oily liquid with a characteristic odour.
It is used as a stain remover and stripper, (including "Superglue"). 16.2.5.1 Azide compounds
Azide compounds, (N3 - ), or (-N3), (-N=N + N-), is usually attached toCarbon, e.g. Phenyl azide (azidobenzene) C6H5N3.
Diazine(diimide) (HN=NH)
Also, salts of hydrazoic acid, HN3, e.g. sodium azide NaN3 16.2.5.2 Azo Compounds
Azo Compounds: derivatives of diazene (diimine, diimide), H2N2, HN=NH, with both hydrogens substituted by hydrocarbyl groups,
e.g. azobenzene or diphenyldiazene (PhN=NPh)
Hydrazone (ketone + hydrazine (N2H4) - water), (RC=NNH2R') 3.00, Benzopurpurin. 16.2.5.3 Diazo Compounds
Diazonium ion R-N + N, diazonium compounds [(RNN + ) Cl - ], e.g. diazomethane, CH2N2
HNO16.7.4 Methylamine ionization reaction
CH3NH2 + H2O <--> CH6N+ and OH-
methylamine + water <--> methylammonium ion + hydroxide ion 16.7.2 Imides
Imides (R1CO-NH-COR2) (imido group: -CONHCO-, e.g. gluthemide C13H15NO2.
The polymer group (-CO-NR-CO), polyimides, N-(trichloromethylthio), cyclohex-4-ene-1,2-dicarboyimide. 16.7.3 Imines
Imines, R2C=NR', Imino group = ring containing (-NH-), or (=NH), linked toC] (RN=CR', where R = H or hydrocarbyl, e.g. (ethyl-), O-benzoquinonedimine
Imine primary RC(=NH)R (imino-) (-imine)
Imine secondary RCH=NR (imino-) (-imine)
Cyclic imines:
Pyrrolines. (dihydropyrroles), are three compounds that differ only in the position of the double bond.
1-Pyrroline, C4H7N, cyclic imine
2-pyrroline, C4H7N, cyclic amine
3-pyrroline, C4H7N, cyclic amine
2-Acetyl-1-pyrroline C6H9NO, bread smell 16.7.5 Nitrosamines
Nitrosamines produced by reaction of nitrous acid with secondary amines and can be formed in the gut if nitrites react with amino acids.
C4 explosive, detonator, solid rocket propellant, mainly cyclonite or cyclotrimethylene trinitramine.
RDX explosive (Research Department Explosive, (O2NNCH2)3, Cyclonite, Hexagen, used against German submarines during World War II.
2 and HCl + R-NH2 --> R-N + N + Cl -
nitrous acid and hydrochloric acid + amines --> diazonium ion + chloride ion
HNO2 + HCl + C6H5NH2 --> C6H5N2Cl + 2H2O
nitrous acid + hydrochloric acid + phenylamine --> benzenediazonium chloride + water
benzenediazonium chloride + phenol --> 4-(phenylazo)phenol + NaCl
benzene-N + NCl - + H-benzene-OH + NaOH --> benzene-N=N-Benzene-OH + NaCl + H2O
4-(phenylazo), phenol is a yellow dye.
Azo dyes of the textile industry use diazonium salts.
The material is first soaked in a soluble salt of phenol or naphthol then soaked in a diazonium salt so that the dye forms in the cloth. 16.7.6 Nitriles
Nitriles are organic compounds containing the −C≡N group.
Cyanides are Inorganic compounds containing the −C≡N group. Nitrile.
Nitriles (acid nitriles, alkyl cyanides, cyanides), (−C≡N, R-C≡N) (note triple bond), Cyanide ion: CN- e.g. ethane nitrile,
Ascetonitrile, (methyl cyanide) CH3CN, 5-methoxyhexanenitrile, CH3C(OCH3)HCH2CH2CH2CN. Acrylonitrile is used for making Orlon (vinyl cyanide, 1-cyanoethene) CH2=CH-CN.
A cyanide contains the cyano group C≡N. 16.7.6.1 Melamine
The cyanamide melamine, C3H6N6, (1,3,5-Triazine-2,4,6-triamine) is 66% nitrogen w/w and is used in the plastics industry.
Melamine, colourless to white monoclinic crystals or white powder, which sublimes when gently heated.
It occurs in Apis cerana, Euglena gracilis, and Aeromonas veronii.
Its high nitrogen content has been the reason for its illegal use as powdered milk pollutant in China,
Melamine has caused death and kidney problems in young babies due to the formation of kidney stones.
Melamine-formaldehyde (MF), 4H6N6O, hard to ignite, alkaline fumes, burns with pale yellow flame (light blue-green edge).
It has a formaldehyde and fish-like smell, thermosetting plastic, it retains strength and shape on heating.
Melamine crockery is sold as being green, virtually unbreakable, dishwasher safe, Not suitable for microwave oven. 16.7.7 Nitrites
Nitrites (NO2-), dioxonitrate ion, salts or esters of nitrous acid, HNO2, (O=NOH)
Nitrites group: -C=N, Suffix: -nitrite, e.g. sodium nitrite NaNO2, potassium nitrite KNO2, used as meat curing agents. 16.7.8 Nitroalkanes
Nitroalkanes (nitroparaffins) CnH2n+1NO2)
Nitromethane CH3NO2, nitroethane C2H5NO2, urea (carbamide) CH4N2O 16.7.10 Organic salts
Organic salts, e.g. sodium ethanoate (sodium acetate) CH3COONa, ammonium acetate CH3COONH4.
NaHCO3 + CH3COOH --> CH3COONa + H2O + CO2 (g). 16.7.14 Phosphorous compounds, organophosphorus insecticides
Captan fungicide: 16.6.3
Organophosphorus insecticides: (mostly thiophosphates), TEPP (tetraethylpyrophosphate, no longer used as insecticide), parathion, maldison (Malathion),
dimethoate (Rogor), dichlorvos (dimethyl dichlorovinyl phosphate, DDVP, Shelltox strips), demetron (Systox). See diagram 16.13.6: captan, glyphosate, paraquat
1. Phosphonic acid, phosphorous acid, H3PO3
2. Phosphonoglycine 16.7.3 Glyphosate, herbicide
3. Organic phosphates: acephate, diazinon, dichlorvos, dimethoate malathion (maldison), naled, parathion 16.7.16Saturated hydrocarbons
Saturated hydrocarbons e.g. hexane, C6H14
All carbon atoms in the compound have either four or three hydrogens bonded to them and no double bonds, triple bonds or rings.
They react in almost the same way, as in ignition test and bromine water test. 16.8.1 Fractional distillation of crude oil
A fractionating column is used to separate the distillates that boil within a temperature range, i.e. the "fractions".
Fractional distillation of crude oil: petroleum gas (LPG), naphtha, petrol (gasoline), kerosene (paraffin oil), diesel oil, lubricating oil (motor oil), paraffin wax (fuel oil), residuals (bitumen, "tar", asphalt, waxes). 16.8.2 Diesel oil
Diesel oil, gas oil or diesel distillate, diesel fuel, heating oil.
Mix of C15H32 toC18H38, 2 or more carbon atoms, alkanes, boiling range 250 oC to 350 oC. 16.8.3 Hydraulic fluid
Hydraulic fluid, mineral oil with low compressibility, needs correct viscosity for different machines. 16.8.4 Kerosene
Kerosene, kerosine, paraffin oil, jet engine fuel, tractor fuel.
Mix of C12H26 toC15H32, 10 to 18 carbon atoms, alkanes and aromatics, boiling range 175 oC to 325 oC. 16.8.5 Lubricating oil, motor oil, grease
Mix of C16H34 toC24H50, 20 to 50 carbon atoms, alkanes and cycloalkanes and aromatics, boiling range 300 oC to 370 oC. 16.8.6 Mineral oil
Mineral oil, low value byproduct of petroleum distillation, usually 15 oC to 40 o C, many uses, lubricating light oil. 16.8.7 Naphtha
Naphtha (petroleum naphtha, ligroin), processed to make gasoline.
Mix of 5 to 9 carbon atoms, mainly aliphatic, e.g. alkanes, boiling range 120 oC to 180 oC, or < 200 oC.
The light hydrocarbon cut between gasoline and kerosene.
(Another naphtha can also be produced from coal tar.). 16.8.8 Paraffin wax
Paraffin wax, heavy gas, fuel oil
Mix of C20H42 and higher hydrocarbons, 20 to 70 carbon atoms, alkanes and cycloalkanes and aromatics, boiling range 370 oC to 600 oC. 16.8.9 Petrol
Petrol, "gas", gasoline, motor fuel
Mix of C6H14 toC11H24, 5 to 12 carbon atoms, alkanes and cycloalkanes, boiling range 40 to 205 oC. 16.8.10 Petroleum gas (methane, ethane, propane, butane)
Mix of 1 to 4 carbon atoms, boiling range < 40 oC.
Liquefied under pressure as LPG (liquefied petroleum gas), a mixture mainly of propane C3H8, and butane C4H10. 16.8.11 Residuals
Residuals, bitumen, "tar", asphalt, waxes
A mix of C24H50 and higher hydrocarbons, multiple-ringed compounds, 70 or more carbon atoms, boiling range > 600 oC.
Petroleum jelly is a saturated semi-solid of crystalline and liquid hydrocarbons, carbon numbers < C25, made by dewaxing paraffinic residual oil.
Naphtha, (Greek naptha fire), was an inflammable bituminous substance used in warfare. 16.10.10 Sulfides
Sulfides: RSR, (R not equal to H), (old name: thioethers)
1. People who eat asparagus may notice a malodorous over-boiled cabbage smell in their urine, because of sulfur compounds, e.g. diallyl disulfide, dimethyl sulfide, dimethylsulfone, sulfimides (sulfilimines): (H2S=NH).
2. Diallyl sulfide, from boiled cabbage
3. Disulfides from crushed garlic
See: Asparagus, (Asparagus officinalis, var. Mary Washington), garden asparagus 16.10.1 Allicin
Allicin, C6H10OS2, diallylthiosulfinate, is produced by crushing garlic, unstable antioxidant, colourless liquid, distinctively pungent smell, defence molecule.
Allicin is produced upon tissue damage from the non-proteinogenic amino acid alliin (S-allylcysteine sulfoxide), catalyzed by the enzyme alliinase.
It is used to treat follicular lymphoma, (FL)
It occurs in onion, garlic, Alliaceae species, and it causes smell of fresh garlic. See diagram 16.2.8.2 : Allicin 16.10.2 Alliin
Alliin, (S-allylcysteine), (3-(Allylsulphinyl)-L-alanine), ACSO, C6H11NO3S, Sulfoxide may cause respiratory irritation, in fresh garlic
It is produced from Cysteine. 16.10.3 Diallyl sulfide
Diallyl sulfide, C6H10S, organic sulfide, Allyl sulfide, Di-2-propenyl sulfide, Thioallyl ether, oil garlic, formed by hydrolysis decomposition of cabbage.
It is a flavouring ingredient, garlic odour, irritates eyes and skin, in animal foods,
It occurs in Allium species, Japanese horseradish Wasabia japonica, black mustard powder Brassica nigra, used in cooked beef, possibly anti-cancer. 16.10.4 Diallyl disulfide
Diallyl disulfide, C6H10S2, Organic Disulfide, Allyl disulfide, in Alliaceae species, insecticidal, antineoplastic, antifungal soil treatment
It has health benefits for most people, but some people are allergic to it.
It occurs in garlic Allium sativum, onion Allium cepa, and in most Allium species. 16.10.5 Diallyl trisulfide
Diallyl trisulfide, Organic Trisulfide, (DATS), Allitridin, S(SCH2CH=CH2)2, di-2-propenyl trisulfide, flavouring, used to treat high blood pressure, high cholesterol, circulatory diseases, antifungal, antitumour, antioxidant, apoptosis inducer, estrogen receptor antagonist, antineoplastic, vasodilator, antioxidant, anti-inflammatory, insecticide, antiprotozoal, platelet aggregation inhibitor, in traditional Chinese medicine, in garden onion (Allium sativum), in garlic oil essential oil from Allium sativum cloves. 16.10.7 Methanethiol from asparagus
People who eat asparagus, which contains methylmethionine, C6H13NO2S and Asparagusic acid, C4H6O2S2 may produce the following malodorous compounds:
Methanethiol, methylmercaptan CH3SH,
Dimethyl disulfide (methyl disulfide) C2H6S2,
Dimethyl sulfone, (methylsulfonylmethane) C2H6O2S.
However, less than 50% of adults can smell these compounds in the urine.
Family studies suggest that the ability to produce the odorous urine is inherited as an autosomal dominant trait.
See: Asparagus, (Asparagus officinalis, var. Mary Washington), garden asparagus 16.10.8 Phenothiazine, PTZ, C12H9NS 11.12.0 Tranquillizers 1, major tranquillizers. See diagram: 14.05, Phenothiazine C12H9NS.
Phenothiazine, light green powder turns green-blue in sunlight, psychoactive drug, antiemetic, antihistaminic, anticholinergic, prevents emesis. 16.10.9 Siloxanes
Saturated silicon-oxygen hydrides with chains of alternating silicon and oxygen atoms,
e.g. unbranched H3Si(OSiH2)nOSiH3, branched H3Si(OSiH2)nOSiH(OSiH2OSiH3)2
"Volasil" is octamethylcyclotetrasiloxane.
Dimethylpolysiloxane is an anti-caking agent, emulsifier and anti-foaming agent. 16.10.11 Sulfonium compounds
Sulfonium compounds: [SR3]+, three organic substituents attached to sulfur
Sulfonium salts, e.g. Trimethylsulfonium chloride CH3)3SCl
Cyclopropyldiphenylsulfonium tetrafluoroborate, C3H5S(C6H5)2BF4
Tris(dimethylamino)sulfonium difluorotrimethylsilicate [(CH3)2N)3S]+[F2Si(CH3)3]−, fluoridation agent 16.10.12 Sulfoxide
Sulfoxide, RS(=O)R', contains a sulfinyl, SO, functional group Alliin, L-alliin, sulfoxide in fresh garlic
Alliin, L-Alliin, C6H11NO3S, S-Allyl-L-cysteine sulfoxide, SAC, aroma of garlic
Dimethyl sulfoxide, DMSO, C2H6OS, from wood pulp, oyster garlic taste, (irritant, penetrates skin, horse liniment, anti-inflammatory, paint stripper, colourless
It is a common solvent and gives garlic taste after skin contact.
Propanethial S-oxide, syn-propanethial S-oxide, (1-sulfinylpropane), C3H6OS, a sulfoxide, a thiocarbonyl S-oxide, volatile liquid, lachrymatory factor
It occurs in sliced Onion, (Allium cepa), Amaryllidaceae.
Broken onion cells --> allinase enzymes + amino acid sulfoxides --> 1-propene sulfenic acid.
Then + lachrymatary factor synthesise enzyme (LFS) --> syn-Propanethial -S-oxide, a lacrimator.
In contact with water in the eye, the lacrimator hydrolyses to propanol, sulfuric acid and hydrogen sulfide, which stings the eyes.
It is relieved by tears from the tear glands. 16.10.13 Thiocyanates
Thiocyanates: SCN−, Salts and esters of thiocyanic acid, HSCN, e.g. methyl thiocyanate C2H3NS 16.10.14 Thiophene
Thiophene, thiolane, THT, CH2)4S, tetrahydrothiophene, colourless, unpleasant odour gas, used as odorant in natural gas and LPG gas (not in USA). 16.11.0 Isothiocyanates 16.11.0 Isothiocyanates
Isothiocyanates, R-N=C=S (old name: mustard oil) (RN=C=S), Mustards: X(CH2.CH2)2S
Isocyanate group, R-N=C=O --> isothiocyanate group R-N=C=S 16.11.1 Allyl isothiocyanate
Allyl isothiocyanate, C4H5NS, (AITC), CH2CHCH2NCS, oil of mustard, mustard oil, colourless to yellow, oily liquid, irritating odour, pungent taste, toxic fumes at high temperature, denser than water, slightly soluble in water, fumigant, rubefacient, in cruciferous vegetables, gives pungent taste of mustard, horseradish, wasabi, apotosis inducer, anti-tumor, anti-oxidant, possibly anti-bladder cancer in:
Black mustard, (Brassica nigra), Brassicaceae Horseradish, (Armoracia rusticana), Brassicaceae Wasabi, (Wasabi japonica), Brassicaceae 16.11.2 Benzyl isothiocyanate
Benzyl isothiocyanate, (BITC), C6H5CH2NCS, C6H5CH2NCS, benyl mustard oil, isothiocyanotaometylbenzene, in cruciferous vegetables, possibly anti-cancer, apotosis, anthelmintic in Papaya seeds 16.11.3 Ethyl isothiocyanate
Ethyl isothiocyanate, CH3CH2NCS, ethyl mustard oil Fluorescein isothiocyanate, (FITC), C21H11NO5S. 16.11.4 Methyl isothiocyanate, (MITC), CH3NCS, soil fumigant, toxic, corrosive, active ingredient in pesticide Metam 16.11.5 Phenethyl isothiocyanate
Phenethyl isothiocyanate (PEITC), C9H9NS, in cruciferous vegetables, watercress, possibly anti-prostate cancer 16.11.6 Phenyl isothiocyanate
Phenyl isothiocyanate, C6H5NCS, (PITC), Edman's reagent, isothiocyanatobenzene, colourless liquid, pungent odour, used for amino acids research to sequence peptides.