Dow Global Technolgoies LLC

John J Anderson

Timothy Charles Frank

Paul Aaron Gillis

Dennis Wade Jewell

Andrei S Merenov

Daniel J Reed

Gerard I Jansma

The present invention a process and apparatus for the production of methylene diphenyl diisocyanate (MDI) isomer mixtures with a low 2,2'-MDI isomer content and a high 2,4&#x2032;-MDI isomer content. The resulting mixtures have an increased reactivity and are acceptable in food grade application due to the reduction in primary aromatic amines formed during the curing process. The process and apparatus also include controlling the amount of 4,4&#x2032;-MDI, which is the most reactive isomer in the mixture allowing use in a wide variety of applications.

Process for the production of methylene diphenyl diisocyanate isomer mixtures with specific isomer distributions and new products derived

A liquid-liquid extraction process that uses counterflowing liquid phases, especially in conjunction with a reciprocating plate extraction column, wherein one of the liquid phases has a lower density than the other and is at least partially saturated with a dispersible gas, requires less plate stack height or a smaller column diameter when plate-to-plate spacing is non-uniform rather than uniform and such non-uniform plate-to-plate spacing includes greater plate-to-plate spacing proximate to raffinate liquid discharge than proximate to feed of the lower density liquid phase.

Liquid-liquid extraction

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Midland, MI, United States of America

John J Anderson