Process for the preparation of hydroxyphenylcarboxylic acid esters using catalytic transesterification

A non-aqueous process for the preparation of a compound of formula (I)

• wherein
• R1 and R2 are independently of one another hydrogen or a linear or branched C1-C8-alkyl,
• m is either 0 or an integer selected from 1, 2 or 3,
• n is an integer selected from 1, 2, 3 or 4,
• and
• A is
• if n is 1, OR3, and R3 is C4-C20-alkyl or C5-C12 cycloalkyl, or
• if n is 2, has the formula —O—CxH2x—O—, O—CxH2x—S—CxH2x—O, —NH—CxH2x—NH— or —O—(CH2CH2O)aCH2CH2O—,
• wherein
• x is an integer selected from 2 to 8, and
• a is an integer selected from 1 to 12,
• if n is 3, has the formula H3C—CxH2x—C(CyH2yO—)3, —O—CxH2x—CH2(O—)—CyH2y—O—,
• wherein
• x,y are independently from one another an integer selected from 1 to 8;
• if n is 4, has the formula —C(—CH2—O—)4
• by a transesterification reaction, wherein a compound of formula (II)
• is reacted with a compound of formula (III)
• and wherein the process step of the transesterification reaction between compound of formula (II) and compound of formula (III) is characterized by being started by the addition of catalyst consisting of an alkali metal bicarbonate or an alkali metal carbonate selected from the group consisting of NaHCO3, Na2CO3, KHCO3 und K2CO3, and which is present in its undissolved solid form.