Patent GB-828441-A (GB)
Title: Production of succinic acids
IPC: E04B2/02
Filed: 1956-03-20
Abstract: Compounds of the general formula <FORM:0828441/IV (b)/1> in which R1 and R2 represent hydrogen or an alkyl, aryl, or alkylaryl radical are obtained by reacting a monoacetylene compound of the general formula R1-C­C-R2, in which R1 and R2 are as defined above with carbon monoxide and water in the presence of a catalyst comprising a carbonyl compound of the type Mem(CO)n, in which Me is a metal of the 8th group of the Periodic System, m is greater than 1 and n is an integer, and in the presence of an organic solvent which is able to dissolve the monoacetylene compound, the water and the catalyst, the reaction taking place in a neutral to acid medium at between 80 DEG and 250 DEG  C. and at a pressure between 100 and 500 atmospheres. In general the integer n in the formula of the catalyst does not exceed the value <FORM:0828441/IV (b)/2> in which Ng is the atomic number of the rare gas following the metal Me in the Periodic System, and Nt is the atomic number of the metal Me, thus in the case of iron n does not exceed 5m.  Examples of suitable carbonyls in which m is greater than 1 which may be used as catalysts are Fe2(CO)9, Fe2(CO)12, Co2(CO)8, Co4(CO)12, Ru2(CO)9, Ru3(CO)12, Os2(CO)9 and Ir2(CO)8.  The metal compounds in which m is greater than 1 may be introduced as such into the reaction or they may be formed during the reaction from simple carbonyls in which m is 1, e.g. Fe(CO)5, Ru(CO)5 and Os(CO)5.  They may also be formed from salts of the metal, e.g. from cobalt or iron succinate, by reacting with carbon monoxide and added hydrogen. It is preferred to use cobalt and iron carbonyl compounds. Suitable solvents are aliphatic and alicyclic ketones such as acetone, methyl ethyl ketone, and cyclopentanone, and ethers such as ethylene glycol dimethyl ether and dioxane.  Specified acetylenic compounds are acetylene, ethyl acetylene, phenyl acetylene, and diphenyl acetylene.  It is desirable to use an excess of water, e.g. about 2.5 mols. of water per mol. of acetylene, and it is preferred to use the solvent in an amount of p  2 to 15 times the weight of water.  The reaction is suitably carried out in an autoclave which contains the reaction medium and the catalyst and into which acetylene and carbon monoxide are introduced until a high partial pressure of CO is reached and the acetylene pressure reached is below the explosion limit.  The process can be carried out intermittently or continuously.  In the latter case the reaction product is at least partially separated from the reaction solution and the remaining liquid (mother liquor) is returned to the reaction chamber together with freshly introduced starting material and this recycling step as well as the operation for the separation of the succinic acid product should be carried out in a carbon monoxide atmosphere and in the absence of oxygen and the partial pressure of carbon monoxide should be higher than the decomposition pressure of the catalytically acting metal carbonyl compound contained in the solution.  After separating the succinic acid, any metal salt of succinic acid, e.g. cobalt succinate or iron succinate, formed during the process from the carbonyl catalyst, can be converted with carbon monoxide and hydrogen at 120 DEG  to 200 DEG  C. and at a carbon monoxide pressure higher than 20 atmospheres into the corresponding metal carbonyl and the liquid containing this carbonyl returned to the reaction vessel. Examples are given for the production of succinic acid together with small amounts of cyclopentanone, acrylic acid, and propionic acid from acetylene by a batch process using dicobalt octacarbonyl, a catalyst formed during the reaction from Fe(CO)5, and a catalyst formed from cobalt succinate by reaction with a mixture of CO and added H2 during the process, respectively, as catalysts and for the production of phenyl succinic acid from phenyl acetylene using dicobalt octacarbonyl as catalyst.  An example for the production of succinic acid from acetylene by a continuous process and comparative examples to show that the process is uneconomical when carried out in the absence of a solvent or if Ni(CO)4 is used as catalyst are also given.