DE2740525A1 - PROCESS FOR MANUFACTURING ALKYL HALOGEN FLAVORS - Google Patents

Description

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Patent application

Applicant: RHONE-POULENC INDUSTRIES

22, avenue Montaigne, Paris (8eW) France

Title: Process for the production of alkyl

halogen aromatic compounds

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description

The invention relates to a new process for the preparation of alkyl halogenated, i.e. alkyl and halogen substituted ones aromatic compounds.

It is known to produce alkyl halogenated aromatic compounds by direct alkylation of a halogenated aromatic with an olefin, a cycloolefin, a halogenated paraffin or cycloparaffin or an alcohol, etc., in the presence of a Friedel Crafts catalyst "to produce (" FRIEDEL CRAFTS and RELATED REACTION "by George A. Olah, Vol. II Interscience Publishers 1963 - J. Wiley and Sons).

The haloaromatics and especially the dihalosubstituted aromatic compounds (o, m or p) can be broken down alkylate in this way only with great difficulty; in addition, o-dichlorobenzene is used as a solvent in certain alkylation reactions (I.e. Volume II, page 67).

A new process has now been developed by means of which halogenated aromatic compounds are easily alkylated permit.

The present invention relates to a process for the production of alkyl haloaromatics which is characterized is that one is a halogen derivative of an aromatic to an isoparaffinic or

naphthenic hydrocarbon in the presence of a Friedel Crafts catalyst and a primary, secondary or tertiary alkyl chloride can act.

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The halogenated aromatics that can be used include the Cg-C ₂₀ mono- or polyhalogenated aromatics, especially chlorobenzenes, bromobenzenes or iodobenzenes, chloro-, bromo- or iodotoluenes, chloro-, bromo- or iodophenols and chloro-, bromo- or iodobiphenyls.

The usable isoparaffin

Hydrocarbons include C ^ -C ™ hydrocarbons like 2,3-dimethylbutane, 2,2,3-trimethylbutane, 2,4-dimethylhexane, 3-ethylpentane, 2,2-methylpentane, isooctane, 2,2,4,6,6-pentamethylheptane and 2,6,10,14-tetramethylpentadecane. Useful naphthenic hydrocarbons are those that have 3 to 12 carbon atoms, such as cyclopentane, methylcyclopentane, Cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, Cycloheptane, cyclooctane, cyclododecane, tetralin, decalin and adamantane.

Usable chloroalkyls are C -, - C ^ Q compounds, preferably C ₅ -C ₈ compounds, such as benzyl chloride, tert-butyl chloride, 4-chloro-2,2,4-trimethylpentane, tert-amyl chloride 2- Chlorine-2,3-dimethylbutane, isopropyl chloride, sec-butyl chloride, chlorocyclobutane, chlorocyclohexane, chlorocyclopentane, 3-chloroheptane and 2-chlorohexane.

The inventive process is carried out at a temperature in the range of 20 to 100 ⁰ C, preferably in the range of 40 to 70 ⁰ C.

Useful Friedel-Crafts catalysts include sulfuric acid, methanesulfonic acid, and zinc chloride in particular Aluminum chloride, hydrogen fluoride and boron trifluoride. How much catalyst is used depends on the nature of the catalyst: If you work with Al ^ Cl, or BF, for example, from 0.01 to 0.5 mol, preferably from 0.02 to 0.1 mol, of catalyst are used per mole of halogen-aromatic compound.

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If hydrogen fluoride (HF) is used, 1 to 30 moles, preferably 2 to 10 moles, of catalyst per mole of halogenated aromatic are used needed.

It is expedient to use 0.1 to 10 moles, preferably 0.4 to 2 moles, of naphthenic or isoparaffinic hydrocarbons to one mole of halogenated aromatic and 0.1 to 2 moles, preferably 0.2 to 1 mole of primary, secondary or tertiary chloroalkyl to 1 mole of halogenated aromatic.

The process according to the invention is carried out in the absence of solvent or in the presence of an excess of generally 200 to 300 % naphthenic or isoparaffinic hydrocarbon.

The alkyl haloaromatics prepared according to the invention are the uses customary for haloaromatics supplied and used in particular as dielectrics or as blending oils or working oils for metals.

The invention is explained in more detail in the following example. In this, the "degree of conversion" is the relative Amount of alkane (obtained from the chloroalkyl used) denotes that, based on the theoretical amount, is released as well as the "yield" is the relative amount of the desired product, based on the theoretically possible Amount obtained with complete and only reaction calculated with reference to the limiting one Reaction partner.

example 1

77.5 g (0.685 mol) of chlorobenzene were placed in a 1 l reaction vessel equipped with a stirrer and thermometer with the aid of a bromine ampoule 17 g (0.174 mol) methyl

cyclohexane and 809812/0 * 7 23

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¹ »8 g (0.0137 moles) of anhydrous aluminum chloride were introduced.

After the temperature of the mixture had reached 4O ⁰ C, in the course of 1 hour was added dropwise a mixture of 12.7 g (0.137 mol) of tert-butyl chloride and 9.8 g (0.1 mol) of methylcyclohexane, corresponding to a molar ratio of alkyl chloride / Chlorobenzene of 0.2; the reaction mixture was then stirred for 3 1/2 hours. The released isobutane was removed during the reaction.

When the reaction had ended, the aluminum chloride was decomposed by adding ice, and the organic phase was also used twice 10% sodium hydroxide solution and then washed twice with water and the aqueous phase extracted twice with ether.

The ether extract and the organic phase were combined and dried. One obtained in this way a mixture of the following composition:

tert-butyl chloride 1.8 g (0.02 mol)

Chlorobenzene 63 g (0.56 mol)

Methylcyclohexane 14.7 g (0.15 mol)

Isobutane 5.22 g (0.09 mol)

Methylcyclohexylchlorobenzene 14.6 g (0.07 mol)

other compounds 2 g.

The desired compound, methylcyclohexylchlorobenzene, was identified by means of vapor phase chromatography and mass spectrometry (M = 208.1018 measured on ^ ⁵ Cl). It consisted of a mixture of isomers, each isomer having the benzene nucleus, a chlorine substituent and a methylcyclohexyl substituent.

The degree of conversion for chlorine was 66 %.

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The yield of the desired compound 51 % · Example 2

The reaction described in Example 1 was carried out at 70.degree carried out under the same conditions with regard to stirring and reaction times, but based on a reaction mixture from:

100.7 grams (0.685 moles) of 1,2-dichlorobenzene

65.1 grams (0.775 moles) of cyclohexane

9.14 g (0.0685 mole) anhydrous aluminum chloride

53.8 g (0.685 mol) isopropyl chloride and

50 grams (0.588 moles) of cyclohexane

corresponding to a molar ratio of alkyl chloride: dichlorobenzene = 1.

After the reaction had ended, the mixture obtained was composed as follows:

Isopropyl chloride 6.67 g (0.085 mol)

1,2-dichlorobenzene 44.1 g (0.3 mol)

Cyclohexane 92.4 g (1.1 mol)

Propane 16.5 g (0.37 mol)

Cyclohexyl dichlorobenzene 54.9 g (0.24 mole) other 3 g.

The desired compound, cyclohexyldichlorobenzene, was identified by means of vapor phase chromatography and mass spectrometry (M = 228.0471, determined on ⁵⁵ Cl). It consisted of a mixture of isomers, each isomer having the benzene ring, two chlorine substituents and one cyclohexyl substituent.

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The degree of conversion for chlorine was 55 %. The yield of the aimed compound was 35 %. Example 3

The procedure was as in Example 1, but at 55 ° C and with the following reaction mixture:

100.7 g (0.685 moles) 1,3-dichlorobenzene 28 grams (0.4 moles) of cyclopentane

1.8 grams (0.0137 moles) of anhydrous aluminum chloride, 63.4 grams (0.685 moles) of tertiary butyl chloride 19.9 grams (0.285 moles) of cyclopentane

corresponding to a molar ratio of alkyl chloride / dichlorobenzene = 1.

After the reaction had ended, a mixture of the following components was obtained:

tert-butyl chloride 18.5 g (0.2 mol)

1,3-dichlorobenzene 41.2 g ^ 0.28 mol)

Cyclopentane 21 g (0.3 mol)

Isobutane 27.8 g (0.48 mol)

Cyclopentyl dichlorobenzene 81.0 g (0.376 mol)

other 5 g.

The desired compound, cyclopentyl dichlorobenzene, was identified by vapor chromatography and mass spectrometry (M = 214.0309, determined on "ei). It consisted of a mixture of isomers, each isomer having a benzene ring, two chlorine substituents and one cyclopentyl substituent exhibited.

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Degree of conversion for chlorine: 70 %.
Yield of aimed compound: 55 %. Example 4

The procedure was again as in Example 1 at a reaction ^{temperature of 60 °} C. and the same conditions with regard to stirring and reaction time, starting from a mixture of the following composition:

107.5 grams (0.685 moles) of bromobenzene

34.2 grams (0.300 moles) of isooctane

4.6 g (0.034 moles) of anhydrous aluminum chloride

31.7 g (0.342 mol) of tert-butyl chloride and

^ 3.9 g (0.385 moles) isooctane

corresponding to a molar ratio of alkyl chloride / bromobenzene of 0.5.

When the reaction was complete, a mixture of the following composition was obtained:

tert-butyl chloride 13.8 g (0.15 mol)

Bromobenzene 78.5 g (0.5 mol)

Isooctane 51.3 g (0.45 mol)

Isobutane 6.9 g (0.119 mol)

Isooctyl bromobenzene 23 g (0.085 mol)

tert-butylbenzene 13.4 g (0.1 mol)

other 7 g.

The desired compound, isooctylbromobenzene, was identified by vapor phase chromatography and mass spectrometry (M = 268.0826, determined on Br); it consisted

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from a mixture of isomers, each isomer having the benzene nucleus, had a bromine substituent and an isooctyl substituent.

Degree of conversion for chlorine: 35 %.

Yield of target compound: 25 %

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Claims (4)

Claims 1. A Process for the preparation of alkyl halogenated aromatics, characterized in that one mono- or polyhalosubstituted Cg to C ₂ o ~ aromatics in the presence
a Friedel-Crafts catalyst with an isoparaffinic C. to C ^ Q hydrocarbon or a C ^ to C. ρ naphthenic hydrocarbon at a temperature of 20 to 10O ⁰ C in the presence of a primary, secondary afer tertiary C ^ to
CjQ-chloroalkyls and 0.1 to 10 moles of naphthenic or isoparaffinic hydrocarbon and 0.1 to 2 moles of chloroalkyl are used per mole of halogenated aromatic. 2. The method according to claim 1, characterized in that there is 0.4 to 1 mole of halogen aromatic Γ moles of naphthenic or isoparaffinic hydrocarbon and 0.2 to 1 mole of chloroalkyl is used. 3. The method according to claim Λ or 2, characterized in that one _{uses a C to C Q} -chloroalkyl. 4. The method according to any one of claims 1 to 3, characterized
characterized in that one is used as halogen aromatic compounds
chlorinated, brominated or iodinated benzenes, toluenes, phenols or biphenyls are used. 7288 809812/0723