Carbonylation of diols and their ethers and esters with ruthenium catalysts: synthesis of lactones and hydroxyacids ethers and esters

Article abstract of DOI:10.1016/S0022-328X(00)99462-2

Diols and their formic or acetic esters can be carbonylated to give lactones or the corresponding hydroxyacid ester or ethers in the presence of carbonylruthenium iodide systems. ^-/alkyl or metal iodide, at a temperature of 200 deg C and CO pressure of 10-20 MPa.The reaction in the case of 1,3-propanediol gives γ-butyrolactone, with a selectivity of 60-70 percent.Side reactions of homologation to 1,4-butanediol derivatives and hydrogenolysis to n-propyl derivatives by H2 produced by the water gas shift reaction (WGSR) also occur, together with acid-catalyzed dehydration to give linear polypropylene glycols, α,ω-diols with more than 3 carbon atoms in the chain preferentially give hydroxyacid esters and ethers.The cyclic ether by-products and linear polyether by-products can be further activated and carbonylated under the reaction conditions to give lactones or hydroxy-acid derivatives thus increasing the total yield of carbonylation products.The formation of H2 by WGSR involving water produced by the acid-catalyzed dehydration reactions, and the subsequent hydrogenolysis and homologation reactions cannot be avoided.