Polymerization of propylene oxide by diethylzinc/ketone catalysts

Abstract

Propylene oxide was polymerized by diethylzinc/ketone system. Cocatalytic effects of twenty-four ketones were examined. Methyl ketones and cyclic ketones were effective as a cocatalyst for the polymerization, while a k y l ketones with longer chain and P-diketon were not. The reaction of the catalyst formation was discussed. Crystallinity of the polymers obtained was compared with that of polymers by diethylzinc/water or diethylzinc/ alcohol catalyst. ZUSAMMENFASSUNG:Propylenoxid wurde mittels eines Diathylzink/Keton-Systems polymerisiert. Es wurde die cokatalytische Wirkung von vierundzwanzig Ketonen gepriift. Dabei zeigten Methylketone und cyclische Ketone eine Wirkung, wahrend aliphatische Ketone mit langerer Kette und 1,3-Diketone unwirksam blieben. Es wurden die Reaktionen, die zur Bildung der Katalysatoren fiihrten, erortert. Die Kristallinitat der erhaltenen Polymerisate wurde mit derjenigen anderer Polymerisate verglichen, die mit Diathylzink/Wasser-und Diathylzink/Alkoholkatalysatoren hergestellt wordep waren.

Organozinc Compounds as Effective Dielectric Modification Layers for Polymer Field‐Effect Transistors

“…Scheme shows the possible mechanism for conversion of DEZn to zinc carboxylates with cyclohexanone as the solvent. The interaction of cyclohexanone and diethylzinc may take place at the carbonyl oxygen and at an active hydrogen simultaneously through a cyclic structure as suggested by Sakata et al (step i in Scheme a) 42. Consequently, an ethylzinc alkoxide was formed by the hydrogen abstraction reaction (step ii in Scheme a).…”

Distillation

“…Ruckenstein (120) and Haddad and Wolf (56) also discussed the general effects of mixing on efficiency. Sakata (123) described equipment and techniques for studying mixing during fractionation conditions in large equipment. Liquid mixing results were reported for sieve trays (78, 81), downcomers (138), slat-trav columns (113), and packed beds (90).…”

Experimental determination of residence time distributions on commercial scale distillation trays using a fiber optic technique

“…column, in which the response to a pulse input of dye was monitored at 3 locations by colorimetric analysis of sample streams which were continuously withdrawn from the bottoms of 3 downcomers. The details of this study have been reported by Sakata (9). Unsuccessful attempts were made to withdraw sample streams from the tray in order to obtain point RTD's and to separate the tray and downcomer effects.…”