Process for producing methylcyclohexyl (METH) acrylates

A methylcyclohexyl (meth)acrylate with formula (I) is prepared by reacting a lower (meth)acrylate (II) with an alcohol (III) in the presence of a transesterification catalyst selected from titanium, tin, zirconium, magnesium, calcium, lithium, potassium or sodium alcoholates; chelates of zirconium, calcium, magnesium or lithium with 1,3-dicarbonyl compounds; dialkyltin oxides, dialkyltin dialkoxides, dialkyltin diesters and distannoxanes and magnesium, calcium or lithium hydroxides. 1 R 1 &equals;CH 3 ; the CH 3 group substituting a cyclohexyl radical in (I) and (III) being able to occupy any of the ortho, meta or para positions; and R 2 &equals;C 1 -C 4 alkyl.

EXAMPLE 1 The following were introduced in succession into a 1 liter glass reactor stirrred with an anchor-type agitator, heated with a double-walled jacket supplied with thermostatted oil and surmounted by a packed distillation column with an efficiency of 4 theoretical plates: 251.2 g of 3-methylcyclohexanol 660 g of MAM; 0.80 g of phenothiazine; and 0.80 g of copper dibutyl dithiocarbamate. The following various operations were carried out in succession: Drying: Heating under reflux at atmospheric pressure, distilling a head containing 0.05% water (fraction F1: 50 g). Throughout the test period, air was bubbled into the reaction mixture. Reacting: When drying was complete, the DBTO catalyst was introduced (8.22 g, i.e., 0.015 mol/mol of 3-methyl-cyclohexanol). The pressure was gradually reduced to 6.66×10 4 Pa (500 mmHg), to keep the temperature in the reactor below 100° C. 125 g of a mixture consisting of 56.9% of methanol and 42.7% of methyl methacrylate was recovered as overhead (fraction F1). The reaction period was 6.5 h. The degree of conversion, calculated from the methanol formed, was >99%. Distilling: The excess MAM and residual traces of alcohol (III) were eliminated by distillation, by gradually reducing the pressure from 6.66×10 4 Pa (500 mmHg) to 3.99×10 3 Pa (30 mmHg) to keep the temperature in the reactor to a maximum of 115° C. (fraction F2: 365 g). The 3-methylcyclohexyl methacrylate was distilled under 2.66×10 3 Pa (20 mmHg) (fraction F3 348 g). The 3-methylcyclohexyl methacrylate finally obtained was a mixture of cis and trans isomers. It was characterized by NMR. 
 EXAMPLES 2 TO 7 Six compounds or mixtures of compounds of the invention were prepared under the same general conditions as those employed in Example 1, varying the MAM/alcohol (III) molar ratio, the nature of alcohol (III), the nature of the catalyst and the amount of the latter. The results are shown in Table 1. 1 TABLE 1 Degree of MAM/ conversion Alcohol of alcohol (III) (III) Selectivity Examples molar ratio Alcohol (III) Catalyst (%) (%) 2 3 4-methylcyclohexanol Zr(acac) 2 >99 >98 0.015 mol/mol alcohol (III) 3 3 3-methylcyclohexanol 69% DBTO >99 >98 4-methylcyclohexanol 31% 0.015 mol/mol alcohol (III) 4 2 3-methylcyclohexanol 69% DBTO 97 >98 4-methylcyclohexanol 31% 0.015 mol/mol alcohol (III) 5 3 3-methylcyclohexanol 69% Zr(acac) 2 99 >98 4-methylcyclohexanol 31% 0.01 mol/mol alcohol (III) 6 2.5 3-methylcyclohexanol 69% Tetrabutyldichlorodistannoxane 98 >98 4-methylcyclohexanol 31% 0.01 mol/mol alcohol (III) 7 3 2-methylcyclohexanol DBTO >99 >98 0.02 mol/mol alcohol (III) The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples. Also, the preceding specific embodiments are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. The entire disclosure of all applications, patents and publications, cited above and below, and of corresponding French application 00/13.672, are hereby incorporated by reference. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.