Apparatus, Systems, and Methods for Purification of Isocyanate Mixtures

Abstract

The present disclosure relates, according to some embodiments, to apparatus, systems, and/or methods for fractionating a feed mixture comprising, for example, one or more isocyanates, light components, solvents and/or heavier components. In some embodiments, fractionating an isocyanate feed mixture may comprise distilling the feed mixture in a non-adiabatic fractionating apparatus comprising a prefractionating section and/or column and a main section and/or column, which comprises a rectification section, a side section, and a stripping section. For example, isocyanates may be separated from light component(s), solvent(s) and/or heavier component(s). A fractionating apparatus may be configured and arranged, in some embodiments, as a dividing wall column. According to some embodiments of the disclosure, apparatus, systems, and/or methods may be energy efficient and/or may have a broad operating range.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61 / 102,128 filed Oct. 2, 2008, entitled APPARATUS, SYSTEMS, AND METHODS FOR PURIFICATION OF ISOCYANATE MIXTURES and U.S. Provisional Patent Application Ser. No. 61 / 102,141 filed Oct. 2, 2008, entitled APPARATUS, SYSTEMS, AND METHODS FOR PURIFICATION OF ISOCYANATE MIXTURES which are incorporated by reference in their entirety.FIELD OF THE DISCLOSURE[0002]The present disclosure relates, in some embodiments, to fractionation of compositions comprising two or more components. For example, the present disclosure relates to distillation of isocyanate mixtures.BACKGROUND OF THE DISCLOSURE[0003]Polyurethane-based foam may be used in a wide variety of products including, for example, automotive crash pads, sound insulation, vibration dampening, carpet backing, bedding, upholstery, furniture, and packing materials. Polyurethanes may be formed by reacting an isocyanate with a polyol. I...

AI Technical Summary

Benefits of technology

[0016]The present disclosure also relates to a distilled isocyanate obtained by a method of the disclosure. A distilled isocyanate may be made bay a process comprising, for example, (a) contacting an aniline with a phosgene under conditions to form an isocyanate-containing feed mixture (e.g., comprises a light component, a middle-boiling component, and a heavy boiling component), and (b) distilling the isocyanate-containing feed mixture in a non-adiabatic fractionating apparatus. In some embodiments, a non-adiabatic fractionating apparatus may comprise a dividing wall column comprising (1) a prefractionating section comprising an upper and lower end and an intermediate reboiler and (2) a main section. A main section may comprise, according to some embodiments, (i) a rectification section in fluid communication with the upper end of the prefractionating section, (ii) a stripping section in fluid communication with the lower end of the prefractionating section, and / or (iii) a side section in fluid communication with the rectification section and the stripping section, wherein a distilled isocyanate is formed. In some embodiments, a non-adiabatic fractionating apparatus may comprise (1) a prefractionating column comprising an upper and lower end and an intermediate reboiler and (2) a main column. A main column may comprise, according to some embodiments, (i) a rectification section in fluid communication with the upper end of the prefractionating column, (ii) a stripping section in fluid communication with the lower end of the prefractionating column, and / or (iii) a side section in fluid communication with the rectification section and the stripping section, wherein a distilled isocyanate is formed. According to some embodiments, the concentration of the light component may be (i) higher than the middle-boiling component and (ii) higher than the heavy boiling component, wherein the concentration of the light component may be from about 5 weight percent or molar percent to about 90 weight percent or molar percent, the concentration of the middle-boiling component may be from about 2 weight percent or molar percent to about 95 weight percent or molar percent, and the concentration of the heavy boiling component may be from about 0.1 weight percent or molar percent to about 50 weight percent or molar percent.

Problems solved by technology

However, this side product stream may be contaminated with light or heavy components depending on its location on the column.

For example, a side product stream may be contaminated by lateral mixing of the components within the column and / or volatiles passing the side outlet on their way to the top of the column.

Problems with contamination may persist, for example, where a feed mixture contains higher levels of lighter components.

Reducing this contamination may require additional columns and / or additional thermal input, which may undesirably increase capital and / or production costs.

Images