IL26343A - Process for the hydrodimerization of acrylic acid derivatives - Google Patents

Description

PATENTS AND DESIGNS ORDINANCE SPECIFICATION Process for of derivatives do hereby and in what manner the same is to be to be particularly and ascertained in and by the following statement The invention concerns the of and nltriles such as to form adipic aoid The acid derivarives prepared in accordance with the present invention are useful as react n e in the manufacture of polyamide fibres and polyamide in She of acrylic aoid derivatives is The processes or proposed for up to now are classifiable two electrolytic hydrogenation reduction by amalgam in some alkaline earth metal present invention concerns a process of the second Known processes for the hydrodimeriaation of acrylic acid derivatives using an alkali metal amalgam all proceed in aqueous media comprising as solute any of the compounds dimethyl sulp methyl dimethyl methyl and various quaternary ammonium The drawback of all these known processes that for the preparation of the aqueous media relatively high proportions of relatively expensive solutes are Even if these solutes are recuperated at the end of the reaction such recuperation invariably involves certain In recuperation often necessitates repeated high liquids resulting in slight decomposition of the latter with the consequential formation of undesirable The present invention is based on the surprising observation that acrylonitrile and aorylonitrlles siay be with the use of an alkali metal amalgam within a reaction medium comprising water and provided the relative proportions of water and ammonia on the hand and the acrylonitrile or acrylonitrile on the other are kept within certain selected Accordingly the invention consists in a process for the of an aorylic acid derivative being acrylonitrile or using an alkali amalgam as reducing wherein the reaction medium is aqueous ammonia in which the ratio is within the range of from to and the amount of the acrylic acid derivative in the reaction mixture is within the range of from 2 to by A preferred range of relative proportio ater is from to A preferred range for the content of the acrylic acid derivative is from 5 to by It known that together with the of aorylic acid derivatives there usually occure a concurring hydrogenation of the It has been observed that when proceeding in accordance with the present invention this concurring reaction occurs only to a relatively small extent and the amount of the hydrogenated monomer does as rule not exceed calculated on the acrylic acid into the and is i most cases She process according to the invention has the great advantage that it uses a cheap reaction medium while at the same producing very satisfactor A further advantage of the process according to the present invention is that no pH control is required and no neutralizing agent need to be added since the reaction medium is alkaline from the outset and any additional amount of free alkali formed the course of the reaction lean The process can be carried out at atures ranging to above room Where the reaction is carried out within the range of from to it is as a rule possible to work with open vessels under atmospheric Against at higher temperatures it is necessary to work in closed From the various alkali metal amalgams can be used for the process according to the invention the sodium and potassium amalgams are preferred on account of their ready The concentration of the alkali metal the amalgam is not oritlcal and may vary within wide the preferred range is within the limit of to by 1 A solution of 10 g acrylonltrile and 90 g of in 30 of was cooled to in a dry In another flask 2 of sodium amalgam by weight of aodium were cooled to the same solution poured onto the and the reaction mixture maintained at under swirling for 5 was then separated distilled the solution diluted with water and extracted with methylene methylene chloride extract contained the reaction chromatographic analysis showed that it consisted of of adiponitrile and of propionitrile calculated on the rile The combined metal conversion yield for adiponitrile and propionitrile was Prom the methylene chloride solution adiponitrile and propionitrile were separately recovered by fractional Methylene chloride and propionitrile distilled under atmospheric pressure adiponitrile was then distilled at a reduced mm g A solution of 10 g of aoiylonltrlle g of ammonia in of water was treated with sodium amalgam as described in Example products obtained consisted of adiponitrile and of propionitrile calculated on acrylonitrile determined as described in Example The metal conversion yield was the recovery of the product from the methylene chloride solution was as in Example of sodium amalgam containing b weight of sodium was introduced into a thick walled flask and 10 g of and 50 of water into another communicating with the The second flask was connected to a vacuum system and also through a control valve to a source of flask the acrylonitrile and water was cooled in liquid air and thereafter the control valve leading to the ammonia source was opened and 50 of ammonia were distilled into the cold Thereafter the flask was sealed off from the vacuum system and also from the The two communicating flasks were introduced into an ice bath and when the temperature reached in both flasks the contents of the two flasks were mixed and the reaction allowed to proceed for 5 minutes under gentle The reaction mixture was worked up and the composition was determined as described in Example The product consisted of of adiponitrile and of propionitrile calculated on the acrylonitrile A solution of 10 g acrylonitrile and 90 g of ammonia in 30 g of water was reacted with kg of amalgam containing by weight of sodium for 15 A sample of the reaction separated from the was extracted with methylene chloride and analysed gas chromatography which showed the product contained of dimethyl adiponitrile and of isobutyronitrile calculated on the acrylonitrile from the aqueous reaction mixture separated from the amalgam the ammonia distilled off and the products were by means of methylene From the resulting extract products were recovered by fractional A solution of 10 g of acrylonitrile and 100 g of ammonia in 30 g of water was reacted with kg of potassium amalgam containin by weight of Procedure in the working up was analogous to that described in Example product consisted of of adiponitrile and of calculated on acrylonitrile fhe metal conversion yield was insufficientOCRQuality

Claims (1)

1. described and ascertained the nature our said invention and in what manner the same is to we declare that for the of an acrylic acid derivative or Using alkali amalgam reducing wherein the reaction is aqueous ammonia in which the ratio is within the range of from to and the amount of the acrylic acid derivative in t reaction mixture is within the range of from 2 to by Process according to wherein the amount of acrylic acid derivative in the reaction mixture is the range of 5 by according to Claim 1 or wherein the ratio in the reaction within the range of from to according to any one of the preceding wherein the acrylic acid derivative used starting material is according to any one of Claims 1 to wherein the acrylic acid derivative used starting material Process according any one of the preceding wherein the is sodium Process according to one of X to wherein the amalgam is potassium Prooesa for the hydrodimerization of an acrylic acid derivative claimed in Claim substantially as described and exemplified Adiponitrile and adiponitrile whenever obtained by a process according to any one of Claims 1 to insufficientOCRQuality