Patent GB-779277-A (GB)
Title: Improvements in the production of acrylic acid esters
IPC: C07C69/54
Filed: 1954-11-04
Abstract: Acrylic acid esters are obtained by reacting acetylene and carbon monoxide with a non-olefinic organic hydroxy compound at elevated temperature and under superatmospheric pressure in the presence of an excess by volume of an organic solvent which is inert under the reaction conditions and miscible with said non-olefinic hydroxy compound and which contains in homogeneous solution a catalytic amount of (a) a halide of a metal of the Iron Group, or (b) a compound of a metal of the Iron Group together with free or combined halogen, for example a halide of a different metal, and as an activator a salt of copper soluble in the reaction medium.  The halide of a metal of the Iron Group may be used in the presence of free or combined halogen.  The reaction may be carried out in the presence of a small amount of water.  It is preferred to use the halides of the Iron Group metals, especially nickel chloride, bromide or iodide.  There may also be used metal carbonyls of metals of the Iron Group prepared per se provided there is present free or combined halogen, e.g. free bromine, hydrogen bromide, or halides of other metals.  Thus mixtures of nickel, cobalt or iron carbonyls in combination with other metal halides may be used as catalyst.  The Iron Group metal halides may also be used in the form of complex compounds with quaternary ammonium or phosphonium halides.  The preferred copper salt activators are copper halides, e.g. chloride, bromide, or iodide but soluble copper salts such as copper sulphate, acetate, or propionate may be used together with halide ions.  If desired a small amount of powdered copper may be added.  A small amount of a conventional polymerization inhibitor, e.g. hydroquinone, may also be added.  Specified non-olefinic hydroxy compounds are non-olefinic alcohols of the aliphatic, araliphatic and cycloaliphatic series, e.g. methanol, ethanol, the butanols, octanols and higher fatty alcohols having straight or branched chains, e.g. octadecanol; cyclohexanol, methyl cyclohexanol, benzyl alcohol and phenylethyl alcohol.  There may also be used polyhydric alcohols, e.g. ethylene, propylene and butyleneglycols and other polymethylene glycols, dihydroxy cyclohexanes, glycerol, pentaerythritol, trimethylol propane and their partial ethers with monohydric alcohols of the above type.  There may also be used phenols, e.g. phenol itself, the cresols, xylenols and higher alkylated phenols, e.g. isobutyl and iso-octyl phenol.  The preferred organic solvents are oxygen-containing water-miscible liquids, e.g. cyclic ethers such as tetrahydrofurane, pyrane and 1,4-dioxane, saturated aliphatic ketones, e.g. acetone, methyl ethyl ketone and diethyl ketone. Cyclic esters and amides, e.g. butyrolactone and N-lower alkyl lactams and particularly N-methyl and N-ethyl pyrrolidones may also be used.  The solvent is preferably one having a boiling point below that of the acrylic ester to be prepared.  It is preferred to use a large excess of solvent, e.g. from 75 to 95 per cent by volume of solvent and 25 to 5 per cent of the alcohol.  The acetylene and carbon monoxide are preferably used in substantially equimolecular ratios but ratios of C2H2:CO of between 0.5:1 to 1:0.5 are suitable. The reaction temperature is preferably from 150 DEG  to 250 DEG  C. and pressures of from 20 to 60 atmospheres are preferred with individual partial pressures of acetylene and carbon monoxide of at least 10 atmospheres.  The reaction may be carried out batchwise or continuously and in the latter case the working liquid may be led downwardly through a reactor charged with filler bodies while the gas mixture is led in the same or opposite direction.  Alternatively, the liquid and gases may be introduced at the bottom of a reactor and the mixture withdrawn at the top. The acrylic ester may be recovered by extraction or by fractional distillation.  In examples: (1), (2) and (12) butyl acrylate, (3), (10) and (11) ethyl acrylate, (4) and (5) methyl acrylate, (6) phenyl acrylate, (7) hydroquinone bis-acrylate, (8) dodecyl acrylate, and (9) butanediol-1,4-bisacrylate are obtained from acetylene, carbon monoxide and the corresponding alcohol or phenol, the reaction being carried out in each case in the presence of a small amount of water.  Generally, a small amount of acrylic acid is also formed.  In (2), (3), (4), (7) and (8) the reaction is carried out in tetrahydrofurane and in the presence of nickel bromide and copper bromide, in (1) and (5) tetrahydrofurane is used with nickel bromide, copper bromide and hydrogen bromide, in (6) tetrahydrofurane is used with nickel bromide and copper chloride, in (9) tetrahydrofurane is used with nickel bromide or nickel iodide, and copper bromide, in (10 and (11) dioxane and acetone respectively are used with nickel bromide and cuprous iodide, and in (12) acetone is used with nickel chloride and cuprous iodide.