PROCEDIMENTO PER LA PRODUZIONE DI ESTERI OSSALICI

• Main Authors: MAKOTO KOBAYASHI HIROSHI MIYAMORI TADASHI SIMOMURA, HIROSHI MASAI
• Format: Patent
• Language: Italian
• Published: 02.07.1981
• Edition: 3
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

Process comprises reacting an aliphatic alcohol with CO and molecular oxygen under heat and elevated pressure. A catalyst consisting of (1) a palladium salt, (2) a copper halide and (3) at least one of nitric acid, nitrogen oxide and nitrous acid ester is used. Oxalic acid ester can be obtd. with high prodn. rate and high selectivity coefft. under mild conditions, a relatively low temp. and low pressure and without using a special dehydrating agent. In an example, in an autoclave equipped with electro-magnetic stirrer are put 40 ml. of methanol and 41.4 mg. (0.18 mmol.), 13.9 mg. (0.14 mmol.) and 2.0 mmol (in terms of HNO3) of fuming nitric acid added. Carbon monoxide gas is then added to the extent of 70 Kg/cm2G at room temp. Then the autoclave is heated up to 75 deg.C, and oxygen gas introduced until the pressure reaches 3 Kg/cm2G. After reaction for 13 minutes, the autoclave is cooled to room temp. The reaction prod. on chromatographic analysis indicates a prodn. of 18.5 mmol. of dimethyl oxalate, 1.0 mmol. of dimethyl carbonate and 0.22 mmol. of methyl formate. The selectivity coefficient of dimethyl oxalate is 93% and the reaction rate is 2.1 mol./litre hour.