6284-75-9Relevant articles and documents
Acrylic Acid from Lactide and Process
-
Page/Page column 3, (2012/04/05)
Technical grade acrylic acid derived from renewable resources utilizing a homogeneous nickel catalyst system by a process including reacting lactide with acetic acid to form 2-acetoxypropionic acid in the presence of a homogeneous nickel catalyst, pyrolyzing, with or without a catalyst, the 2-acetoxypropionic acid to acrylic acid and acetic acid, condensing and collecting the pyrolysis products in the presence of polymerization inhibitor(s) and purfying the acrylic acid by distillation in the presence of polymerization inhibitor(s). Acrylic acid and methyl acrylate are produced from methyl 2-acetoxypropionate which comes from fermentation derived lactic acid. The disclosed process will produce a “green” (i.e. renewable resources derived) acrylic acid and methyl acrylate ester.
The methoxycarbonylation of vinyl acetate catalyzed by palladium complexes of [1,2-phenylenebis(methylene)]bis[di(tert-butyl)phosphine]
Rucklidge, Adam J.,Morris, George E.,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
, p. 1783 - 1800 (2007/10/03)
Palladium complexes of [1,2-phenylenebis(methylene)]bis[di(tert-butyl) phosphine] (1) catalyze the methoxycarbonylation of vinyl acetate (=ethenyl acetate) in the presence of methanesulfonic acid (Scheme 1). High selectivities to ester products can be obtained if free phosphine ligand is in excess over the amount of added acid (Table 1). Selectivities to methyl 2-acetoxypropanoate, a precursor to lactate esters, can be as high as 3.6:1 at low temperature and pressure (Table 2). Replacing tBu by iPr groups leads to less-active catalysts and lower selectivities to the branched product. Replacing the phenylene moiety by a naphthalenediyl moiety also gives lower activity, but with similar selectivity to the phenylene-based analogues. Linear hydrocarbon-chain linkers as the backbone instead of the phenylenebis(methylene) linker leads to poor catalysis, except for a propane-1,3-diyl linker, which gives good rates but poor branched selectivity (Table 5). The effect of different reaction conditions on the catalysis is discussed. The syntheses of the new xylene-based diphosphines 2-5 with one to four iPr groups replacing the tBu groups at the P-atoms of 1 and of the ligands 6 and 7 based on 1,2- and 2,3-dimethylnaphthalene are also described (Schemes 2 and 3).
Process for the preparation of 2-hydroxy carboxylic acids
-
Page/Page column 2, (2008/06/13)
A two step preparation for hydroxy carboxylic acid (e.g. lactic acid) is disclosed. An enol ester (e.g. vinyl acetate) is carbonylated in the presence of a hydroxyl compound (e.g. methanol) using a palladium catalyst having one or more O-, N- and/or P-containing ligands (e.g. PdCl2(PPh3)2), and a solvent at 50-150° C./50-2000 psig to yield hydroxy ester (e.g. methyl lactate) and acetoxy ester (e.g. methyl-2-acetoxy propionate). The second step involves hydrolyzing the products of the carbonylation step using acid catalysts (e.g. TsOH, aq HCl, resin) at 10-125° C. to produce 2-hydroxy carboxylic acids (e.g. lactic acid). The carbonylation and hydrolysis catalysts may be separated and recycled.