| 摘要 |
1361952 Methylene and oxymethylene dicarboxylic acid esters CHEVRON RESEARCH CO 23 Jan 1973 [24 Jan 1972 30 Oct 1972] 3487/73 Heading C2C Methylene or oxymethylene dicarboxylic acid esters of formula where R is C 1 to C 10 alkyl, C 7 to C 10 alkaryl, C 7 to C 10 aralkyl or phenyl and n is 1 to 5 are prepared by reacting a carboxylic acid of formula RCOOH, ethylene, carbon monoxide and formaldehyde in the presence of a catalyst system comprising a rhodium compound and an iodide or bromide promoter. The formaldehyde may be formed in situ from paraformaldehyde or trioxane, and when R is ethyl the propionic acid may be formed in situ by reaction of ethylene carbon monoxide and water. Exemplified rhodium compounds are rhodium halides, rhodium carbonyl halides, Rh 2 O 3 , and coordination compounds such as Rh[(C 6 H 5 ) 3 P] 3 (CO)I and RhCl- (CO)[(C 6 H 5 ) 3 As] 2 . Suitable iodide and bromide promoters include HBr, HI, Br 2 I 2 and alkyl bromides and iodides having 1 to 6 carbon atoms and 1 to 3 bromide or iodide groups. The iodide and/or bromide moieties may be incorporated in the rhodium compound so that a separate iodide or bromide promoter is not necessary, e.g. RhI[(C 6 H 5 ) 3 P] 3 , RhI 3 and RhBr 3 . |
