# US 2013/0156677 A1 · Process for separating monosilane from chlorosilanes-rich mixture

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- Number: US 2013/0156677 A1
- Document ID: US20130156677A1
- Status: Published application
- Kind: A1
- Application number: 13/820,386
- Filed: 2011-08-29
- Published: 2013-06-20
- Earliest claimed: 2010-09-03
- Assignees: L'Air Liquide, Societe Anonyme pour I'Etude et l'Exploitation des Procedes Georges Claude
- Inventors: Isao Abe; Shinji Tomita
- Web page: https://patentgrep.com/patent/US20130156677A1

## CPC

- C01B 33/046: {Purification}
- C01B 33/043: {Monosilane}
- B01D 53/002: {by condensation}
- B01D 2257/553: Compounds comprising hydrogen, e.g. silanes
- B01J 31/0237: {Amines}
- B01J 31/0239: {Quaternary ammonium compounds}
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A process for separating monosilane from a mixture comprising monosilane and chlorosilanes comprising: a) Introducing mixture to a condenser (3) for separating lower-boiling chlorosilanes—containing monosilane from higher-boiling chlorosilanes enriched condensates; b) Collecting said higher-boiling condensates, in a condensate buffer (19) connected to the aforesaid condenser (3) by a condensate feed pipe (8); c) Sending higher-boiling chlorosilanes enriched condensates from the aforesaid condensate buffer (19) into a subcooler (21) which is installed on a reflux feed line (7) connected to the upper portion of a chlorosilane absorber (20); d) Feeding lower-boiling chlorosilanes—containing monosilane to the aforesaid chlorosilane absorber (20) for separating monosilane; e) Extracting monosilane—rich gas from the upper portion of the aforesaid chlorosilane absorber (20).

## Claims

### Claim at position 1

1-10. (canceled)

### Claim 11

A process for separating monosilane from a mixture comprising at least monosilane, monochlorosilane, dichlorosilane, and trichlorosilane comprising:
a) introducing said mixture to a condenser (3) for separating lower-boiling chlorosilanes-containing monosilane from higher-boiling chlorosilanes enriched condensates;
b) collecting said higher-boiling condensates, in a condensate buffer (19) connected to the aforesaid condenser (3) by a condensate feed pipe (8);
c) sending higher-boiling chlorosilanes enriched condensates from the aforesaid condensate buffer (19) into a subcooler (21) which is installed on a reflux feed line (7) connected to the upper portion of a chlorosilane absorber (20);
d) feeding aforesaid lower-boiling chlorosilanes-containing monosilane to the aforesaid chlorosilane absorber (20) for separating monosilane;
e) extracting monosilane-rich gas from the upper portion of the aforesaid chlorosilane absorber (20);
characterized in that only one condenser (3) is used during the process.

### Claim 12 (depends on 11)

The process of claim 11, further comprising the step:
f) extracting a pure monosilane gas from a distillation column (22) downstream the chlorosilane absorber (20).

### Claim 13 (depends on 11)

The process of claim 11, wherein step c) comprises subcooling higher-boiling chlorosilanes enriched condensates by a refrigerant and serving as a reflux to the upper portion of the aforesaid chlorosilane absorber (20).

### Claim 14 (depends on 13)

The process of claim 13, wherein the refrigerant is chosen from Brine (Lithium bromide, Calcium Chloride, Sodium chloride, Magnesium chloride), Chlorofluorocarbon (commonly called as Freon), Ammonia, Hydrocarbon, and an antifreeze solution (like aqueous Ethylene glycol).

### Claim 15 (depends on 11)

The process of claim 11, wherein said mixture comprises:
more than 50 mol % of a mixture comprising monochlorosilane (MCS), dichlorosilane (DCS), trichlorosilane (TCS) and tetrachlorosilane (STC); and
from 0.1 to 40 mol % of monosilane.

### Claim 16 (depends on 11)

The process of claim 11, wherein said monosilane-rich gas comprises more than 60% mol of monosilane.

### Claim 17 (depends on 11)

The process of claim 11, wherein during step d) the separation of monosilane in the aforesaid absorber (20) is a distillation.

### Claim 18 (depends on 12)

The process of claim 12, further comprising:
g) extracting chlorosilane condensates from the bottom portion of the aforesaid chlorosilane absorber (20) to be recycled.