DD160222A3 - PROCESS FOR THE PREPARATION OF TERTIAN MERCAPTANES - Google Patents

Abstract

Claim: Process for the preparation of tert. Mercaptans from tertiary olefins and hydrogen sulfide, in the presence of an aluminum complex catalyst, characterized in that are used as catalysts liquid complex compounds of AlCl 3 ind with alkylaromatics and hydrochloric acid, preferably toluene and / or ethylbenzene and / or diethylbenzene.

Description

158592

Process for the preparation of tertiary mercaptans

The invention relates to a process for the preparation of tert. Mercaptans by reaction of a tert. aliphatic olefin with hydrogen sulfide in the presence of a catalyst.

It is known that tert. Olefins of the structure

R-iv ^ Rq

¹ C = C _x ^J , vto Rj, R ₂ , Ro lind Ά * same or

C: Π 9

various alkyl radicals or derivatives may be used - but R /, and R ₂ and also S-, and R ^ are not the same ^{. 'J} time may be hydrogen in the presence of _s AlCIo |

Mercaptans show "It is also known to carry out the synthesis of mercaptans from the corresponding hydrocarbon compounds in the presence of Friedel-Craft catalysts and hydrogen halides! It is also known to use Friedel-Craft catalysts in combination with organic solvents for the synthesis of tertiary mercaptans from olefins. A major disadvantage of these processes is the low conversion due to the heterogeneous character (fee t / 11 ssig) ,

In order to achieve a better conversion, it has already been proposed to use AlClO in the form of a mercaptan or nitroalkane complex salt solution. In the presence of these complex salt solutions, especially with nitroalkane solutions - tert, olefins and hydrogen sulfide react to form tert. Mercaptans. The disadvantages of these processes are the fragmentation, which is too high for a technical process, when using AlClo-nitroalkane complex salt solutions and the resin formation when using AlClo-mercaptan complex salt solutions, which leads to a gradual yestering of the reactor walls.

Purpose of the invention is _s to reduce the fragmentation and the formation of resin in the synthesis of mercaptans.

The invention has for its object to provide a process for the preparation of tert. To develop mercaptans by means of a catalyst which exhibits at least the same activity as that of the previously proposed a lower fragmentation 'at temperatures of 1.0 to 50 ° C and no wall encrustation of the reactor.

The object has been achieved in that for the preparation of tert. Mercaptans from tert-olefins and hydrogen sulfide as catalysts liquid complex compounds of AlClO with A.lky! Aromatics + HGl or

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their solutions are used · With good conversion and high yields, the mercaptan formation proceeds with pure tert.-olefins or isomer mixtures in which the proportion of isomers with tert. Double bonds predominates. Such olefins are, for example, the di-, tri- or letramers of propylene or isobutylene or mixtures thereof.

The new catalyst system lowers fragmentation over the known AlCl 2 -titanium alkane complex compounds and shows no resin formation. in the reaction of triisobutylene, the amount of tert. Butyl · · and tert. Octylmercaptan at 15.degree.-20.degree. C. on average by 2.9 times and at 2.4.degree. C. on average by 5.degree. C. after completion of the reaction, the complex compound settles out as U1 and shows no wall encrustation as in the case of Use of AlCltMercaptankomplexverbindungen was observed.

The AlCl ^ -Alkylbenzol üCl complex compounds prepared by known methods are of oily consistency and can also be used without a diluent.

The catalyst system AlCIa-Ai frylaromaten-MCl is very stable and shows no reduction in activity even after several days of storage.

The reactions of tert.-olefins with hydrogen sulfide in the presence of the new complex catalyst can be carried out continuously or batchwise at atmospheric pressure and higher pressure and temperatures of up to 50 ° C. The yields in all cases are 9o f or above, while the conversions are dependent on the type of olefin with regard to its isomer composition. They are z, Bu for isobutylene of the n ^ value

1.4367 ca, $ 80 > and for setrapropylene over $ 85 >

The invention will be explained in more detail with reference to the following Ausführungsbei games *

In a glass reaction flask equipped with a mobile stirrer and with one stub for the addition of catalyst, the hydrogen sulfide inlet and outlet, 300 g of Sriisobutylene with a value of 1.4367 were added, 15 min. rinsed with dried nitrogen and then saturated for 3o minutes at 1 5 ° C with dry hydrogen sulfide with vigorous stirring.

8 g of a complex salt solution of AlCla-toluene-JiCl, which has a molar ratio of 1: 3: 0.6, were added portionwise through a dropping funnel under light nitrogen pressure, the hydrogen sulphide supply being adjusted according to consumption, adding the entire amount of catalyst flat At a temperature of 1 ο »2 ° ° C, hydrogen sulphide was introduced until no further uptake took place. Uach 3o minutes was the reaction is complete, "For the deactivation of the catalyst were I00 ml of o, added 2 #ige HCl, then was in a scabbard funnel 2 2: each 5oo ml o, 2 #iger MCI and 1 χ with 5oo ml distilled * Washed water. The separated from the aqueous layer mixture of mercaptan and unreacted olefin was worked up in a known manner

|. | ;. ·; It was received?

ti '""

k, tert-butyl-mercaptan 2 g

tert »Octyl mercaptan 4.6 g

tert »Dodecylmercaptan 25S _S 3 g

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Distillation residue 5 g

No wall encrustation of the reaction vessel.

Example 2

If the experiment mentioned under Example 1 is carried out with 3 g of triisobutylene at 5 ° C. with 3 g of the same i-complex salt solution (corresponding to 0.93 g of AlCla), the following are obtained:

tert. Butyl mercaptan 2.4 g

tert. uoty! mercaptan 4.1 g

tert. Dodeoy! Mercaptan 252 g

Distillation residue 5 g

No wall encrustation of the reaction vessel.

Example 3

Under the same conditions as in Example 1, 3oo g of tetrapropylene (Bjj-1f4359) were reacted with hydrogen sulfide in the presence of a complex solution of AlCl.sub.3 / ethylbenzene / HCl, which gave the individual components in the MoI ratio of 1 s contained (3.14 g AlCl ₃ ), reacted.

Result: lower mercaptans than CqHjqSH

calculated: 4.5 g

tert · dodecylmeroaptan 30 g

Distillation residue 6 g

Turnover on iCetrapro! Py ^ n || ^ ⁵ ? 89 * 1 $ Yield of tert-dodeylated mercaptan: 96.5

No wall encrustation of the mercaptan reactor.

Claims (2)

158 claims 1. A process for the adjustment of tert-hercaptans from tertiary ulefins and hydrogen sulfide, in the presence of an aluminum complex catalyst, characterized in that are used as catalysts liquid complex compounds of AlGIo with alkylaromatics and hydrochloric acid, preferably toluene and / or ethylbenzene and / or diethylbenzene. 2. The method according to claim 1, characterized in that the complex compounds of AlGl ₃ with alkylbenzene § · HCl without diluent in a molar ratio AlCl ₃ j alkylbenzene 1 5 2 to 1 5 3 and AlCl ₃ : HGl 1: o, 5 to 1 j Used Oj8