| 摘要 |
<p>The invention relates to a method for the synthesis of diacids or diesters of the general formula ROOC-(CH2)X-COOR in which n is an integer between 5 and 14, R is either H or an alkyl radical with 1 to 4 carbon atoms, from natural long-chain mono-unsaturated fatty acids or esters including at least 10 adjacent carbon atoms per molecule of the general formula CH3-(CH2)n-CHR1- CH2-CH=CH-(CH2)p-COOR, in which R is H or an alkyl radical with 1 to 4 carbon atoms, R1 is either H or OH, and n and p are equal or different and are indices between 2 and 11. The method comprises: during a first step, converting the natural fatty acid or ester by pyrolysis or ethenolysis into a ?-mono-unsaturated fatty acid or ester of the general formula CH2=CH-(CH2)m- COOR in which m is equal to p or p+1 depending on the natured of the processed fatty acid/ester and the conversion used; during a second step, submitting the product thus obtained to a metathesis or homometathesis reaction for obtaining a compound of the general formula ROOC-(CH2)m-CH=CH-(CH2)m-COOR, or a crossed metathesis reaction with a compound of the formula R2OOC-(CH2)-CH=CH-R3,in which R2 is her H or an alkyl radical with 1 to 4 carbon atoms, r is either 0 or 1 or 2, and R3 is H, CH3 or COOR2 thus defining a cyclic molecule or not, in order to obtain an unsaturated compound of the genera formula ROOC-(CH2)m-CH=CH- (CH2)-COOR2; and, during a third step, converting the unsaturated compound into a saturated compound by hydrogenation of the double bond.</p> |
