# US 4,395,542 A · Process for removing trace amounts of epichlorohydrin from heat sensitive glycidyl products

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- Number: US 4,395,542 A
- Document ID: US4395542A
- Status: Granted
- Kind: A
- Application number: 06/340,674
- Filed: 1982-01-19
- Granted: 1983-07-26
- Earliest claimed: 1982-01-19
- Assignees: Ciba-Geigy Corporation
- Inventors: Yel S. Sury
- Web page: https://patentgrep.com/patent/US4395542A

## CPC

- C07D 405/14: containing three or more hetero rings
- C07D 301/32: Separation; Purification
- C07D 303/24: with polyhydroxy compounds
- C07D 303/36: with hydrocarbon radicals, substituted by nitrogen atoms (nitro, nitroso radicals C07D303/08)
- C08G 59/00: Polycondensates containing more than one epoxy group per molecule (low-molecular-weight polyepoxy compounds C07); Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

Epichlorohydrin levels in heat sensitive glycidyl products are reduced from a few thousand ppm, an unacceptable level, to only a few ppm or to a non-detectable level by use of a multistage stripping column with or without inert gas purging without decomposition of the heat sensitive glycidyl products. Such glycidyl products are useful in epoxy resins particularly as crosslinking agents.

## Claims

### Claim 1

A method of preparing an epoxy resin or product containing glycidyl groups, essentially free of residual epichlorohydrin and associated volatile material, which comprises
heating an epoxy resin or product containing glycidyl groups, which still contains excessive amounts of residual epichlorohydrin and associated volatile materials, to a temperature of 60.degree. to 250.degree. C., a temperature sufficient to allow said resin or said product to flow easily, but insufficient to cause thermal decomposition thereof, and
passing the heated resin or product one or more times through a packed column or multistage evaporation stripper, to effect multistage stripping of said resin or product, at a temperature of 60.degree. to 250.degree. C. and at a pressure of 1 to 500 mm Hg, to reduce the level of epichlorohydrin and associated volatile materials in the heated resin or product to less than 10 ppm.

### Claim 2 (depends on 1)

A method according to claim 1 wherein the epoxy resin or product containing glycidyl groups is heated to a temperature of 80.degree. to 180.degree. C. and is subjected to multistage stripping at a temperature of 80.degree. to 180.degree. C.

### Claim 3 (depends on 1)

A method according to claim 1 wherein the multistage stripping is carried out at a pressure of 6 mm Hg or less.

### Claim 4 (depends on 1)

A method according to claim 1 wherein the heated epoxy resin or product containing glycidyl groups is purged with an inert gas during the multistage stripping.

### Claim 5 (depends on 4)

A method according to claim 4 wherein the inert gas is nitrogen.

### Claim 6 (depends on 1)

A method according to claim 1 wherein the epoxy resin is 2,2-bis(4-glycidyloxyphenyl)propane.

### Claim 7 (depends on 1)

A method according to claim 1 wherein the product containing glycidyl groups is N,N,O-triglycidyl-p-aminophenol.

### Claim 8 (depends on 1)

A method according to claim 1 wherein the product containing glycidyl groups is N,N,N',N'-tetraglycidyl-4,4'-methylenedianiline.

### Claim 9 (depends on 1)

A method according to claim 1 wherein the product containing glycidyl groups is triglycidyl isocyanurate.

### Claim 10 (depends on 1)

A method according to claim 1 wherein the product containing glycidyl groups is N,N-diglycidyl-5,5-pentamethylenehydantoin.