# US 2021/0277035 A1 · Preparation of isocyanatosilanes

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- Number: US 2021/0277035 A1
- Document ID: US20210277035A1
- Status: Published application
- Kind: A1
- Application number: 17/259,268
- Filed: 2019-07-02
- Published: 2021-09-09
- Earliest claimed: 2018-07-13
- Assignees: Momentive Performance Materials Inc.
- Applicants: Momentive Performance Materials Inc.
- Inventors: Venkata Sunil JAGANI; Srinivas KOMATI; Vivek KHARE
- Web page: https://patentgrep.com/patent/US20210277035A1

## CPC

- C07F 7/1804: {Compounds having Si-O-C linkages (Si-O-acyl linkages C07F7/1896)}
- C07F 7/1892: {by reactions not provided for in C07F7/1876 - C07F7/1888}
- B01D 3/009: {in combination with chemical reactions}
- B01D 3/143: {by two or more of a fractionation, separation or rectification step}
- B01D 3/32: Other features of fractionating columns {; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30}
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

There is provided herein a method and an apparatus for producing an isocyanatoorganosilane which method includes feeding a carbamatoorganosilane to a cracking device where it is thermally dissociated into a reaction product mixture comprising isocyanatoorganosilane, alcohol, and heavies, followed by separating the mixture in a distillation column of two parts and collecting the isocyanatoorganosilane from the distillation column via a side stream having a predetermined location between the top and bottom parts of the column; and wherein the distillation column is configured to have a ratio of the length of the bottom part of the distillation column to the length of the top part of the distillation column which is effective to provide a side stream having a high purity and high weight percent of isocyanatoorganosilane.

## Claims

### Claim 1

A method for producing a high purity isocyanatoorganosilane of the general formula (I)
R2R3R4Si—R1—N═C═O (I),
comprising:
(A) feeding a carbamatoorganosilane of the general formula (II)
R2R3R4Si—R1—NH—CO—OR (II),
where
R is a monovalent alkyl radical containing from 1 to 10 carbon atoms or an aromatic group of from 6 to 12 carbon atoms,
R1 is a divalent hydrocarbon radical containing from 1 to about 6 carbon atoms, and R2, R3 and R4 are independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, methoxy, ethoxy, n-propoxy and isopropoxy radicals, to a cracking device;
(B) heating the fed carbamatoorganosilane to a temperature and pressure effective to thermally dissociate the carbamatoorganosilane to a reaction product mixture comprising isocyanatoorganosilane, alcohol, unreacted carbamatoorganosilane, and heavies,
(C) separating isocyanatoorganosilane having a purity greater than about 90% from the rest of the reaction product mixture in a distillation column having a bottom part and a top part, and
(D) collecting the isocyanatoorganosilane having greater than about 90% purity through a side stream which is located between the bottom part of the distillation column and the top part of the distillation column and
wherein the ratio of the length of the bottom part of the distillation column to the length of the top part of the distillation column is from about 2:1 to about 10:1.

### Claim 2 (depends on 1)

The method of claim 1, wherein the ratio of the bottom part of the distillation column to the length of the top part of the distillation column is from about 3:1 to about 5:1.

### Claim 3 (depends on 1)

The method of claim 1, where the method is a continuous method.

### Claim 4 (depends on 1)

The method of claim 1, where the carbamatoorganosilane is such that R is a monovalent alkyl radical containing from 1 to about 3 carbon atoms, R1 is a divalent hydrocarbon radical containing from 1 to about 3 carbon atoms, and R2, R3 and R4 are independently selected from the group consisting of methyl, ethyl, methoxy, and ethoxy radicals.

### Claim 5 (depends on 1)

The method of claim 1, where the carbamatoorganosilane is selected from the group consisting of methyl N-(3-trimethoxysilypropyl) carbamate, ethyl N-(3-triethoxysilypropyl) carbamate and combinations thereof.

### Claim 6 (depends on 1)

The method of claim 1 wherein the temperature and pressure effective to thermally dissociate the carbamatoorganosilane are from about 150° C. to about 300° C. and from about 2 to about 500 mbar.

### Claim 7 (depends on 1)

The method of claim 1, where the isocyanatoorganosilane is selected from the group consisting of 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane and combinations thereof.

### Claim 8 (depends on 1)

The method of claim 1, wherein step (B) further comprises employing a catalyst.

### Claim 9 (depends on 1)

The method of claim 1 wherein step (B) further comprises adding a solvent to the cracking device.

### Claim 10 (depends on 1)

The method of claim 1, further comprising removing the heavies from the cracking device.

### Claim 11 (depends on 1)

The method of claim 1, further comprising conveying the isocyanatoorganosilane and alcohol in the reaction mixture of step (B) as a vapor mixture to the top part of the distillation column.

### Claim 12 (depends on 11)

The method of claim 11, wherein step (C) further comprises removing the alcohol from the vapor mixture and condensing the isocyanatoorganosilane into the liquid phase by a partial condenser positioned above the top part of the distillation column, and reintroducing the liquid phase into the top part of the distillation column to provide the separated isocyanatoorganosilane having a purity greater than about 90%.

### Claim 13 (depends on 1)

The method of claim 1, wherein the purity of the isocyanatoorganosilane which is separated in step (C) and collected in step (D) is greater than about 92%.

### Claim 14 (depends on 1)

The method of claim 1, wherein the yield of isocyanatoorganosilane collected in step (D) is greater than or equal to about 60% based on the weight of collected isocyanatoorganosilane relative to the weight of fed carbamatoorganosilane.

### Claim 15 (depends on 1)

The method of claim 1, wherein the yield of isocyanatoorganosilane collected in step (D) is greater than or equal to about 65% based on the weight of collected isocyanatoorganosilane relative to the weight of fed carbamatoorganosilane.

### Claim 16 (depends on 1)

The method of claim 1, wherein the side stream of step (D) is located at an exit point from the bottom part of the distillation column.

### Claim 17 (depends on 1)

The method of claim 1, wherein the isocyanatoorganosilane having greater than about 90% purity which is collected through a side stream in step (D) is removed from the distillation column at a rate that provides for a hydrodynamically stable system.

### Claim 18 (depends on 1)

The method of claim 1, wherein the distillation column is a single distillation column.

### Claim 19

A distillation column having a top part and a bottom part, wherein the top part has a top exit point and a bottom entrance/exit point and the bottom part has a top exit point and a bottom entrance/exit point, and wherein the ratio of the length of the bottom part of the distillation column to the length of the top part of the distillation column is from about 2:1 to about 10:1, and wherein a side stream take-off is positioned at a location at the top exit point of the bottom part.

### Claim 20 (depends on 19)

A distillation system comprising the distillation column of claim 19, and further comprising a partial condenser located above the top part of the distillation column and connected thereto through the top exit point.

### Claim 21 (depends on 20)

The distillation system of claim 20, further comprising a cracking device located below the bottom part of the distillation column and connected thereto through the bottom entrance/exit point.