Arco Chemical Technology, L.p.

T Thomas Shih

John C Jubin, Jr

Te Chang

Jose F Pazos

Wilfred P Shum

William J Sim

A continuous process for the preparation of polyoxyalkylene polyethers using DMC catalysts as the polyoxyalkylation catalyst employs continuous addition of alkylene oxide in conjunction with continuous addition of starter and catalyst to a continuous oxyalkylation reactor. Despite the continuous introduction of starter, the molecular weight distribution of the polyether product is quite narrow, as indicated by the exceptionally low polydispersity of the product. The presence of low molecular weight species during the majority of the polyoxyalkylation also substantially eliminates extremely high molecular weight fractions having molecular weights greater than 100,000 Da, again without appreciably broadening molecular weight distribution. By withdrawing intermediate molecular weight polyether product or diverting a portion of the end product to prepare a catalyst/starter mixture, rapid and sustained reaction rates can be achieved while employing low molecular weight starters. Continuous build ratios in excess of 0.98 can be achieved.

Continuous preparation of low unsaturation polyoxyalkylene polyether

The method for the separating close-boiling impurities from propylene oxide essentially free of high molecular weight poly (propylene oxide) which comprises contacting the impure propylene oxide with solid activated carbon adsorbent and separating propylene oxide reduced in impurities content from the adsorbent.

Propylene oxide purification

A method of recovering optically active epoxy alcohols from asymmetric epoxidation reaction mixture is provided whereby the epoxy alcohol may be obtained in high yield with minimal degradation of optical purity. The process is also suitable for the synthesis of useful organic sulfonate derivatives of chiral epoxy alcohols.

Process for recovering an optically active epoxy alcohol

The method for the separating close-boiling impurities from C.sub.2 -C.sub.4 l alkylene oxide which comprises contacting the impure alkylene oxide with solid activated carbon adsorbent and separating alkylene oxide reduced in impurities content from the adsorbent.

Lower alkylene oxide purification

The present invention provides an improved process for the separation of impurities from a lower alkylene oxide, such as propylene oxide, by a process wherein the impure propylene oxide is first fractionally distilled to separate higher and lower boiling impurities, then the partially purified alkylene oxide is subjected to extractive distillation to separate additional impurities, the purified propylene oxide being separated as an overhead fraction.

A method is provided for the separation by extractive distillation of hydrocarbon impurities from lower alkylene oxides such as propylene oxide wherein a glycol having 2 to 5 carbon atoms is used as extractive solvent.

The method for the separating methyl formate from lower alkylene oxide such as propylene oxide which comprises contacting the impure alkylene oxide with basic ion exchange resin and separating alkylene oxide reduced in methyl formate content.

A method is provided for the separation by extractive distillation of hydrocarbon impurities from propylene oxide wherein t-butyl alcohol/water is used as extractive distillation solvent.

A method is provided for the separation by extractive distillation of oxygenated impurities from a monoepoxide while avoiding epoxide loss, wherein lower glycol is used as extractive solvent in amounts so as to provide only up to about 0.3 mol % solvent in the vapor in the extractive distillation zone.

Monoepoxide purification

Purification of tetrahydrofuran from the dehydrocyclization of 1,4-butanediol in the presence of an organic acid catalyst has been accomplished by the extractive distillation of crude tetrahydrofuran containing water using monopropylene glycol as an extractive solvent.

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Bryn Mawr, PA, United States of America

T Thomas Shih