Process for the alkoxycarbonylation of alcohols

A process for forming an ester mixture product having n- and iso-ester components from a corresponding first alcohol substrate and CO and a second alcohol comprising the following process steps:

• a) introducing the first alcohol selected from a secondary or tertiary alcohol, having 2 to 30 carbon atoms, to form a reaction mixture;
• b) adding a phosphine ligand and a compound which comprises Pd, or adding a complex comprising Pd and the phosphine ligand;
• c) adding the second alcohol;
• d) supplying CO;
• e) heating the reaction mixture, the first alcohol reacting with CO and then the second alcohol to form the ester mixture with the iso- and n-products;
• where the phosphine ligand is a compound of formula (I)
• where m and n are each independently 0 or 1;
• R1, R2, R3, R4 are each independently selected from —(C1-C12)-alkyl, —(C3-C12)-cycloalkyl, —(C3-C12)-heterocycloalkyl, —(C6-C20)-aryl or —(C3-C20)-heteroaryl, where each is substituted or unsubstituted;
• and
• at least one of the R1, R2, R3, R4 radicals is a —(C3-C20)-heteroaryl radical;
• wherein
• the substituents are selected from
• —(C1-C12)-alkyl, —(C3-C12)-cycloalkyl, —(C3-C12)-heterocycloalkyl, —O—(C1-C12)-alkyl, —O—(C1-C12)-alkyl-(C6-C20)-aryl, —O—(C3-C12)-cycloalkyl, —S—(C1-C12)-alkyl, —S—(C3-C12)-cycloalkyl, —COO—(C1-C12)-alkyl, —COO—(C3-C12)-cycloalkyl, —CONH—(C1-C12)-alkyl, —CONH—(C3-C12)-cycloalkyl, —CO—(C1-C12)-alkyl, —CO—(C3-C12)-cycloalkyl, —N—[(C1-C12)-alkyl]2, —(C6-C20)-aryl, —(C6-C20)-aryl-(C1-C12)-alkyl, —(C6-C20)-aryl-O—(C1-C12)-alkyl, —(C3-C20)-heteroaryl, —(C3-C20)-heteroaryl-(C1-C12)-alkyl, —(C3-C20)-heteroaryl-O—(C1-C12)-alkyl, —COOH, —OH, —SO3H, —NH2 or halogen.