Patent GB-769563-A (GB)
Title: Improvements in or relating to the preparation of acrylic esters
IPC: C07C69/54
Filed: 1954-01-12
Abstract: Acrylic esters are obtained by reacting together at between 30 DEG and 90 DEG  C. acetylene, nickel carbonyl, an acid which forms a nickelous salt from the nickel carbonyl in the reaction mixture and which makes available for reaction the carbonyl therefrom, and a monohydric alcohol of 3 to 12 carbon atoms, and, while these substances are reacting passing into the reaction mixture and there reacting at between 30 DEG  and 90 DEG  C. acetylene, carbon monoxide, nickel carbonyl, water and the said alcohol.  The initial reaction may be carried out in the presence of water.  The process is of particular value for forming acrylic esters of tertiary alcohols and allylically unsaturated alcohols but may also be applied to C3-C12 alkanols, to ether alcohols, and to alicyclic alcohols including terpenic alcohols. Specified alcohols are unsaturated alcohols of the formula R1CH= CR2-CH2OH, where R1 is hydrogen, an alkyl group or the phenyl radical and R2 is hydrogen, phenyl, chlorine, or an alkyl group, e.g. allyl, 2-methallyl, 2-ethallyl, 2-butallyl, 2-phenylallyl, 2-chloro-allyl, neopentylallyl, crotyl, 3-ethallyl, 3-butallyl, and cinnamyl alcohols.  Also specified are tertiary butyl, tertiary amyl, isopropyl, n-butyl, hexyl, octyl, 2-ethyl hexyl, isononyl, dodecyl, terpineols, e.g. a -terpineol, cyanoalkanols, chloroalkanols and ether alcohols.  The acid used may be a monocarboxylic acid having up to four carbon atoms, acrylic acid or acetic acid being preferred, although propionic, butyric, and methacrylic acid may also be used.  Strong acids, e.g. hydrochloric acid, may be used in the case of alcohols other than the allylic alcohols.  The reaction may be carried out in the presence of an inert organic solvent, e.g. acetone, methyl ethyl ketone, dioxane, benzene, toluene, or mixtures of such solvents. It is desirable to use an excess of water, e.g. about 150 to 400 per cent of the amount of water theoretically equivalent to the nickel carbonyl.  The molar ratio of carbon monoxide to the amount of carbon monoxide supplied by the nickel carbonyl should be between 20 : 80 and 70 : 30 and about 0.9 mol. to 1.1 mols. of acetylene should be used per mol. of total CO.  The process is normally carried out at atmospheric pressure although higher or lower pressures may be used and it may be carried out batchwise or in a continuous manner.  Any nickel carbonyl which remains in the reaction mixture may be consumed by continuing the flow of acetylene to decompose the carbonyl and the reaction mixture may then be worked up by washing with water to separate ester and nickel salt and the nickel can be recovered and re-converted to nickel carbonyl which may be returned to the process, whilst the ester may be recovered by distillation of the ester phase. Examples are given for the production of tertiary butyl acrylate, allyl acrylate, n-butyl acrylate, sec.-butyl acrylate, n-octyl acrylate, 2-ethoxyethyl acrylate, allyl acrylate, methallyl acrylate, capryl acrylate, cyclohexyl acrylate, tertiary amyl acrylate and a -terpinyl acrylate.  Acrylic acid is used in each case as the acid and some free acrylic acid is also formed along with the first two mentioned esters.  Specification 708,007 is referred to.