APPROACHES TO SELECTION OF TECHNOLOGIES FOR PROCESSING OF THE POLYCARBONATES PRODUCTION BY-PRODUCTS. MESSAGE 1: ANALYSIS OF COMPOSITION FOR THE ETHYLENE CARBONATE PRODUCTION BY-PRODUCT
Ethylene carbonate (EC) is produced at Kazanorgsintez PJSC by reaction of ethylene oxide with carbon dioxide using a potassium iodine catalyst. This process is characterized by high selectivity and environmental friendliness. The release of target product, EC, is carried out in film-type steamers. At the bottom of columns, a by-product of the EC production is formed, which is a brown solid substance, odorless, with the EC mass fraction of at least 65%. Using gas chromatography, IR spectroscopy, and crystallization, it was found that by-product of the EC production is a complex mixture of components, the main of which is EC (78.9%), as well as monoethylene glycol, MEG (0.8%), triethylene glycol, TEG, (3.7%); fraction of heavy components is 16.6%. Glycols in the composition are in an associated state. There are no bands corresponding to the free hydroxyl group in the IR spectra of MEG, diethylene glycol (DEG), and TEG, since formation of inter- and intramolecular associates due to H-bonds is characteristic for these glycols. The characteristic frequencies, 3362 cm-1 for MEG and 3374 cm-1 for DEG and TEG, indicate the content of polyassociates in these glycols.