Patent GB-1439234-A (GB)
Title: Vicinal glycol ester preparation process
IPC: B01J31/00
Filed: 1973-08-09
Abstract: 1439234 Vicinal glycol esters HALCON INTERNATIONAL Inc 9 Aug 1973 [9 Aug 1972] 37735/73 Heading C2C [Also in Division Bl] Mono- and diesters of vicinal glycols are obtained by the reaction of ethylene and/or propylene with molecular oxygen and at least one C 1-5  monobasic saturated aliphatic hydrocarbyl carboxylic acid, said at least one acid being in excess of that stoichiometrically required, in the liquid phase at between 150 and 250 C. in the presence of a catalyst comprising one or more of (i) Te+Br, (ii) Se+Br and (iii) Se+Cl and at least one basicity control cation in an amount to provide at least 0.05 gram (equivalent (e.g. 0.2 to 3.0) of basicity control cation per gram-atom of total halogen present, said cation having, when in the form of a salt with the halide(s) of the catalyst system, an activity coefficient of at least 0.40 determined at 25 C. in aqueous solution of concentration 0À1 N or saturated, whichever is the more dilute and said cation not having a pH- reducing effect when in the form of a salt(s) with the carboxylic acid reactant. Presence or absence of a pH-reducing effect is determined by comparison of the pH of a 0.1 N or saturated aqueous solution of the carboxylic acid reactant, whichever is the more dilute, with the pH of an otherwise identical solution which also contains 0.1 equivalent of the basicity control cation or which is saturated with respect to the cation salt if this requires less than 0.1 equivalent. The solutions are heated to 50 C. in sealed containers, maintained at 50 C. for 6 hours, cooled to 25 C. and the pH measured. An absence of a pH reducing effect is indicated if the pH of the solution comprising the cation is equal to or greater than the pH of the standard acid solution. More than one of said basicity control cations may be present and specified cations are those formed from alkali metals, alkaline earth metals, the lanthanides, Sc, Y, Fe, Co, Ni, Zn, Bi, Cr, Mn, Mo, Cu, As, Sb, alkyl amines, phenyl amines, alkyl quaternary ammonium salts, pyrrole, pyridine, indole and alkylsubstituted pyrroles, pyridines and indoles. In a preferred embodiment, the reactants are continuously introduced into the oxidation zone and at least a portion of the liquid phase is continuously withdrawn, the withdrawn portion being processed to recover ester products, unconverted reactants and halogenated by-products and the unconverted reactants and at least a major portion of the halogenated by-products being recycled to the oxidation zone. Examples describe the reaction of ethylene or propylene with formic, acetic, propionic and valeric acids using as basicity control cations those formed from Li, Mg, Zn, Ca, Mn, Ni, Ce, As, Sb, Na, Fe, Cr, Mo, Sc, Y, Bi, Cu, (C 2 H 5 ) 3 N, pyridine, pyrrole, indole, triphenylamine and (C 2 H 5 ) 4 NOH. Control runs presented for comparison include the preparation of 2,3-diacetoxybutene from butene-2 and acetic acid, the use of Te + Cl as the catalyst system and the use of cations of Ag, Hg, Cd or Pb and of H 2 SO 4 , in place of the basicity control cations.