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Pyrolysis

Oxidation to cyclohexanol and cyclohexanone

liquid and gas phases

Oxidation to adipic acid

Nitration

Photonitrosation

Chlorination

Reactions of cyclohexanone - preparation of

Caprolactam and dicarboxylic acids

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Condition: 500 oC, without catalyst

Products: butadiene, ethylene, hydrogen, propylene

If cyclohexene, 500 600 oC, low pressure, to produce butadiene

and ethylene

Additional information: at 300 oC, atmospheric, catalyst: Pd or Pt,

to produce benzene

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Polyvalent metal salts such as cobalt, form cyclohexanone and cyclohexanol

Secondary alkyl peroxide, decomposition of hydro-peroxide

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Precursor: methylcyclohexane

Reagents: air (1:5 v/v naphthene : air)

Catalyst: silver oxide on asbestos

Condition: 400 500 oC

Products: methylcyclohexanones

Hydrogen attached to the tertiary C is not preferable

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Precursor in the production of nylon 6

Two types: one-step and two-steps processes

One-step reaction

Condition: Liquid phase, 95 oC, 11 atm

Reagents: CH3COOH, HCl, cobalt hexahydrate

Air bubbled through the mixture

Additional information: Hoot and Kobe, oxidize N2

to produce NO2, 50 oC, 98% yield

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Two-step reaction

First step (to produce a mixture of cycohexanol-cyclohexanone)

Oxidation of cyclohexane at 125 160 oC, 4 18 atm

Catalyst: cobalt naphtenate

Second step (to produce adipic acid)

Reagents: 40% nitric acid solution, ammonium metavanadate, Cu

Condition: 50 150 oC, 4 18 atm.

Recrystalline, separation by centrifuge, 60 -70 % yield

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Two step reaction (continue)

Alternative condition: 60 80 oC, 1 4 atm

Reagents: air, 50 60 % nitric acid, Cu and V salts

92 98 % yield, complete conversion of cyclohexanol-cyclohexanone

Adipic acid may also converted to adiponitrile and hexamethylene

diamine for the production of nylon 6-6

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Liquid phase nitration

Reagent: 35 % nitric acid

Condition: 120 125 oC, 4 5 atm

60 % yield

Alternatively: nitric acid, dispersion of molten salt

Condition: 400 oC

Gas phase nitration

Reagent: nitrogen dioxide

What we can do to nitro compounds?

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Photochemical reaction

Condition: -10 16 oC, Hg lamp 20 kW, light exposure at 600 nm or less

Product: cyclohexanone oxime hydrochloride

Preparation of nitrosyl chloride

Oxidation of ammonia to nitrogen sesquioxide (N2O3)

Treated with H2SO4 at atmospheric pressure to produce nitrosylsulphuric acid

Reacted with preheated HCl to produce NOCl

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Reagents: 3% benzoyl peroxide, PCl3

Condition: 25 40 oC, UV irradiation

73 74 % yield, distillation to produce a colourless oil, terpene-likeodor

Use as insecticide

Additional information: commonly chlorination being used or reacted

with benzene

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Important precursor for the preparation of nylon

Use of cyclohexane converted to cyclohexanone or nitrocyclohexane

Cyclohexanone to an oxime

Reagent: hydroxylamine hydrochloride

Beckman rearrangement to produce caprolactam

Reagent: ~60% sulfuric acid

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Reduction of nitrocyclohexane to cyclohexanone oxime

Reagents: ammonium sulfide or sodium bisulfide

Alternative reagents (by Grundman):

ammonia, Raney Ni and trace of alkali

Alternative procedure:

Reagent: MeOH or EtOH with ammonia, Ni-Cr

Condition: heating under pressure

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Oxidation

In the presence of air and under pressure

Catalyst: manganese or cobalt salts

Condition: 200 oC, air pressure at 25 atm

Yield: cyclopentanone glutaric acid,

methylcyclohexanonemethyladipic acid

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Reaction with carbon dioxide

Alternative route to produce dicarboxylic acid compounds

Catalyst: reduced manganese chromite, free acetic acidCondition: aqueous cyclohexanone, 200 oC, 20 hs, under CO2pressure

Yield: pimelic acid

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Production of naphthenes

Physical treatments azeotropic / extraction distillation

Chemical treatments dehydrogenation-hydrogenation, ringclosure, ring enlargement

Reactions

Pyrolysis to produce alkene

Oxidation to cyclohexanol and cyclohexanone liquid and gasphases

Oxidation to adipic acid

Nitration

Photonitrosation

Chlorination

Reactions of cyclohexanone - preparation of Caprolactam and

dicarboxylic acids

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Caprolactam is a cyclic amide of caproic acid. Beside its disadvantages to our health(cause skin and eye irritation, toxic to digestion and inhalation systems), it is a primaryindustry in textile.

Describe the chemical process in the production of nylon-6 from caprolactamincludes alternative process.

Suggest another three compounds / substances / applications of caprolactam.Give your justification (or references) to your suggestions. It is recommendedfor suggesting green chemistry. OR

Describe health and environmental issues relating to the production ofcaprolactam and their derivatives. Suggest how you could counter theproblem.

At least 3 pages A4 (or around 6,000 characters or 1,000 words)

Font: either Times New Roman or Arial

Font size: 12 with 1.5 spacing

Full mark: 15 marks

Format: Soft-copy, then email to me..!