Bp Chemicals Limited

David J Drury

John E Hamlin

Peter S Williams

Alexander G Kent

John Pennington

Jeffrey J Anderson

Process for the preparation of formic acid

A carboxylic acid of formula RCO.sub.2 H where R is a C.sub.1 to C.sub.10 aliphatic hydrocarbyl group is prepared by heating under substantially anhydrous conditions an ester of formic acid of formula HCO.sub.2 R where R is as defined above in the presence of carbon monoxide and an effective amount of a catalyst system comprising a Group VIII metal, a halide and a compound containing a quaternary Group V atom. The quaternary Group V atom can be formed in situ by adding a compound containing a trivalent nitrogen, phosphorus or arsenic atom quaternizable under the reaction conditions and a quaternizing agent. Acetic acid is prepared by heating methyl formate in the presence of a catalyst system containing a rhodium compound, an iodide and a quaternary nitrogen-containing heterocyclic base.

Process for the preparation of acids

Methyl formate is produced continuously by reacting methanol in the liquid phase with molecular oxygen in the presence as catalyst of a soluble chromium compound which can be deliberately added or can result from corrosion of a reaction vessel fabricated in stainless steel or other chromium-containing metal alloy. Initiation of the oxidation can be accomplished by feeding a material more susceptible to oxidation than methanol, either with or without methanol, and optionally in the presence of a soluble chromium compound.

Continuous process for the production of methyl formate by the chromium

A carboxylic acid or an ester thereof having at least two carbon atoms more than formic acid is prepared by reacting at elevated temperature e.g. 100.degree. to 250.degree. C. formic acid or a formate ester with an olefin e.g. ethylene in the presence of, as catalyst, a Group VIII noble metal e.g. iridium, preferably promoted by iodide, to cause addition of the formic acid or ester to the olefin and form the a higher acid e.g. propionic acid or ester thereof. A strong acid such as a sulphonic acid may be used as a copromoter. The catalyst is employed in solution.

Preparation of carboxylic acids and esters thereof

Formate salts of nitrogenous bases containing tertiary nitrogen are prepared by reacting the nitrogenous base with carbon dioxide and hydrogen using a soluble transition metal catalyst. For example triethylamine is reacted with carbon dioxide and hydrogen using ruthenium trichloride as catalyst and an isopropanol/water mixture as solvent to yield triethylammonium formate which was separated from the reaction mixture by distillation.

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David J Drury