Preparation and Pyrolysis of Lactic Acid Derivatives. Production of β-Alkoxyethyl and Tetrahydrofurfuryl Acrylates²

Bioderived Acrylates from Alkyl Lactates via Pd-Catalyzed Hydroesterification

“…With the demonstration that compounds 2a and 2b could be prepared in very high yields using low levels of Pd and easily isolated by distillation, we sought to investigate whether the pyrolysis of the propionyloxy esters would also result in alkyl acrylate formation as in the case of the acetoxy analogues. − Compound 2a was added dropwise with a flow of CO 2 gas into a vertical quartz tube heated to 550–560 °C and packed with 1 g of silicon carbide supported on quartz wool (see SI for full details). After complete addition over the course of ∼50 min, a crude oil was obtained, the 1 H NMR spectrum of which was relatively clean and was shown to be composed mostly of a mixture of methyl acrylate, propionic acid, and propionic anhydride (Figure ).…”

“…However, these routes generally suffer from limited conversions and yields. − Early work from the 1930s and 1940s also showed that pyrolysis of alkyl 2-acetoxypropanoate derivatives, which can be obtained from alkyl lactates directly by acetylation, gives the corresponding alkyl acrylates in varying yields with acetic acid as the coproduct in an atom economic process (Scheme ). − The nature of the alkyl (R) group of the starting lactate was shown to significantly affect the yield of the acrylate ester obtained. , Newer work in this area has focused on the nickel catalyzed acetylation of lactide (the cyclic dimer of lactic acid) with acetic acid to give 2-acetoxypropionic acid, which can be subsequently pyrolyzed to give acrylic acid or converted to the methyl ester for production of methyl acrylate . This route is attractive in that it gives high yields of acrylic acid or methyl acrylate from lactide, and utilizes readily available nickel­(II) nitrate and nickel­(II) acetate as the acetylation catalysts, but requires somewhat harsh conditions.…”

Acetylation of Alkyl Lactates and Similar Hydroxy Esters with Acetic Acid

“…The infrared spectra of polymers provide approximate information about the proportions of 1,2 and 1,4 polymerizations (21). The spectra of pure samples of known structure (1-octene and 2octene) and their known mixtures are used to calibrate the instrument, but the direct application to polymer spectra involves the assumption that other structural variations are without effect on the absorption bands (7).…”

“…B., Ibid., 63, 1483 (1941). (7) Frankel, J. S., Stonebruner, W., and Brown, J. B., Ibid., 65, 259 (1943) .…”

“…lactates can be made in large quantities at low cost (21), and their acyl derivatives (alkyl «-acyloxypropionates, Equation 1) are of value as solvents, plasticizers (1, 2), and intermediates for the pyrolytic preparation of methyl acrylate (3,19) and certain other polymerizable esters (7,11,20). Thus far, ketene (4), vinyl acetate (15, 16), acid anhydrides (6), and acid chlorides (6) have been used in the acylation of alkyl lactates.…”