4374-57-6Relevant academic research and scientific papers
PROCESS FOR PREPARING CYCLIC ESTERS AND CYCLIC AMIDES
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Page/Page column 30-32, (2014/08/20)
The invention relates to a process for preparing a cyclic ester or a cyclic amide, comprising the step of: contacting at least one hydroxycarboxylic acid and/or at least one amino-carboxylic acid; or an ester, or salt thereof; wherein said hydroxycarboxylic acid is a 2-hydroxycarboxylic acid,or a 6–hydroxycarboxylic acid; and wherein said amino carboxylic acid is a 2-amino-carboxylic acid or a 6-amino-carboxylic acid; with at least one acidic zeolite comprising: - two or three interconnected and non-parallel channel systems, wherein at least one of said channel systems comprises 10-or more-membered ring channels; and a framework Si/X2 ratio of at least 24 as measured by NMR; or - three interconnected and non-parallel channel systems, wherein at least two of said channel systems comprise 10-or more-membered ring channels; and a framework Si/X2 ratio of at least 6 as measured by NMR; wherein each X is Al or B, and wherein the process is performed at a pressure between 0.5 and 20 bar.
Condensation of Glycolic, Lactic and 2-Hydroxybutanoic Acids during Heating and Identification of the Condensation Products by GLS-MS
Alen, Raimo,Sjoestroem, Eero
, p. 633 - 636 (2007/10/02)
Glycolic, lactic and 2-hydroxybutanoic acids are partly converted to various condensation products during heating.This conversion was studied at 100 deg C and 125 deg C by identifying the trimethylsilylated products consisted of both linear (dimers and trimers) and cyclic (dimers) structures.The influence of the condensation on the recovery and purification of the hydroxy acids by distillation is discussed.
