DE880136C - Process for the production of adipic acid dinitrile - Google Patents

Description

As starting materials for the valuable adipic acid and the compounds adipic dinitrile which can be prepared from it and hexamethylenediamine are technically only cyclohexanol or cyclohexanone Question. The adipic acid obtainable from these technically valuable starting materials can, however, be used the adipic dinitrile produce only in unsatisfactory yield.

It has now been found that adipic acid

Dinitrile can be obtained from cheap raw materials available in large quantities if one prepares butyne-2-diol-1,4-butyne-2-diol-1,4 by the process of patents 725 326 and 726 714 by the action of acetylene on formaldehyde, this in a known manner or in the liquid phase use, or hydrogenated nickel or cobalt skeletal catalysts and nickel or cobalt on pumice fuller's earth silica, asbestos or aluminum oxide by passing under an elevated pressure at temperatures below 150 ⁰ with an excess of hydrogen over nickel and cobalt catalysts for butane-i, 4, butanediol -i, 4 converted in a known manner into 1,4-dihalobutane and in this, as is known, the halogen atoms are replaced by cyano groups.

The first stage of the process, the production of butyne-2-diol-i, 4 from formaldehyde and acetylene, happens, as mentioned, according to the method described in patents 725 326 and 726 714. The hydrogenation of butyne-2-diol-i, 4 to butanediol-i, 4 is carried out with the help of noble metal catalysts

in a manner known per se (cf.reports of the Deutsche Cherri. Gesellschaft, vol. 56, pp. 187 to 192, and Vol. 60, pp. 1125 to 1130; Chemical Abstracts, Vol. 28, pp. 1669 to 1670; Ann. de Chimie et de Physique [8], Vol. 30, pp. 524 to 529). You can also in the manner described above with nickel or Hydrogenate cobalt catalysts. From the 1,4-butanediol, the 1,4-dihalobutanes can be converted into Customary manner, for example by treatment with thionyl halides (see. Houben, methods of Organic Chemistry, 3rd ed., Vol. 3, p. 1123). The 1,4-dihalobutanes are converted into adipic dinitrile in a known manner (see Beilstein, Handbook of Organic Chemistry,

4th ed., Vol. 2, p. 653), for example by heating with alkali or alkaline earth cyanides.

In the new way, Adipinsäuredinitril from the technically easy, cheap and in any Produce amount of accessible starting materials formaldehyde and acetylene. The individual stages of the Process can also be carried out on a large scale with very good yields, both of adipic acid also on hexamethylenediamine, based on formaldehyde and acetylene.

The parts given in the example are parts by weight, unless otherwise noted.

example

50 "parts of 30% aqueous formaldehyde solution is filled with a catalyst consisting of 1 part of acetylene copper and 0.15 part of acetylene silver to 2 parts of fuller's earth into a stirred autoclave and then passes an acetylene-nitrogen mixture in a volume ratio of 2: 1 at 100 ° pressure, whereupon it permanently nachpreßt acetylene, is more added to nothing. After separation of the catalyst is obtained as an approximately 35% aqueous solution of butyne-2-diol-i, 4, in a yield of 90 ° / ₀ Theory, of which one pumps 300 parts by volume with hydrogen per hour through a vertically standing vessel which contains 1900 parts by volume of a nickel catalyst applied to pumice stone. The hydrogen used for hydrogenation is under 200 atm pressure; it is circulated ^{at a reaction temperature of 50 0} out. when distilling the final solution to 4 in 97 ° / _o yield is obtained pure butane-i,., 90 parts thereof are allowed at ordinary temperature under constant stirring flow sam in 260 parts of thionyl chloride. The mixture is then gradually heated to 80 ° and kept at this temperature until the evolution of gas has ceased. The distillation then gives 116 parts of 1,4-dichlorobutane, corresponding to a yield of 90% of theory. This product is dissolved in the same amount of methanol and heated together with 110 parts of technical grade sodium cyanide in a stirred autoclave at 150 ^0th The reaction has ended after 5 hours. Is obtained from the reaction mixture by filtering off the sodium chloride formed by distillation adiponitrile in 87 ° / _n yield.

Claims (1)

Claim: Process for the preparation of adipic dinitrile, characterized in that butyne-2-diol-1,4 is prepared by the process of patents 725 326 and 726 714 by the action of acetylene on formaldehyde, this either in a known manner or in the liquid phase using Nickel or cobalt skeleton catalysts or nickel or cobalt on pumice stone, fuller's earth, silica gel, asbestos or aluminum oxide or by conducting under increased pressure at temperatures below 150 ⁰ with excess hydrogen over nickel and cobalt catalysts to give butanediol-i, 4, this in converted into 1,4-dihalobutane in a known manner and in this, as is known, the halogen atoms are replaced by cyano groups. Referred publications: Beilstein, Handbook of the organ. Chemie, 4th ed., Vol. II, p. 653 5204 6.