# US 10,766,853 B2 · Catalytic process for preparing N,N-dimethylglucamine from N methylglucamine

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- Number: US 10,766,853 B2
- Document ID: US10766853B2
- Status: Granted
- Kind: B2
- Application number: 16/495,370
- Filed: 2018-02-28
- Published: 2020-01-16
- Granted: 2020-09-08
- Earliest claimed: 2017-03-20
- Assignees: Clariant International Ltd.
- Applicants: Clariant International Ltd.
- Inventors: Ertan Akgün; Martin Link; Sarah Werner; Klaus Raab; Peter Klug; Karl Scheitzeneder; Stefan Kreuzpointner
- Web page: https://patentgrep.com/patent/US10766853B2

## CPC

- C07C 213/08: by reactions not involving the formation of amino groups, hydroxy groups or etherified or esterified hydroxy groups
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The invention relates to a method for preparing aqueous solutions of N,N-dimethylglucamine, characterized by first preparing an adduct of N-methylglucamine and formaldehyde in water at temperatures of between 15° C. and 40° C., and subsequently reacting said adduct to N,N-dimethylglucamine in the presence of a metal catalyst under hydrogen pressure at 20-68° C., followed by secondary hydrogenation at 70-120 bar and 70-110° C. once hydrogen absorption at 20-68° C. is completed.

## Claims

### Claim 1

A process for preparing N,N-dimethylglucamine comprising the step of reacting an aqueous solution of N-methylglucamine first with an aqueous solution of formaldehyde at 15-40° C. and subsequently, at a pressure of 20-120 bar and a temperature T=30-68° C., with hydrogen under metal catalysis, wherein, after absorption of hydrogen has completed at 20-68° C., a further, after-hydrogenation is added at 70-120 bar and at 70-110° C.

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein the metal catalyst is Raney nickel.

### Claim 3 (depends on 1)

The process as claimed in claim 1, which is carried out at a hydrogen pressure of 70-110 bar.

### Claim 4 (depends on 1)

The process as claimed in claim 1, wherein the hydrogenation is carried out at 35-65° C.

### Claim 5 (depends on 1)

The process as claimed in claim 1, wherein the molar ratio of N-methylglucamine to formaldehyde is 1:1 to 1:1.5.

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein the hydrogenation catalyst is reused more than 5 times.

### Claim 7 (depends on 1)

The process as claimed in claim 1, wherein reaction takes place in a stirred reactor or loop reactor.

### Claim 8 (depends on 1)

The process as claimed in claim 1, wherein the remaining N-methylglucamine content is <2wt %.

### Claim 9 (depends on 1)

The process as claimed in claim 1, wherein the residual formaldehyde content is <0.1 wt %.

### Claim 10 (depends on 1)

The process as claimed in claim 1, in which the Hazen color number of the resulting solution of N,N-dimethylglucamine is <500.

### Claim 11 (depends on 1)

The process as claimed in claim 1, in which the molar ratio of N-methylglucamine to formaldehyde is 1:1 to 1:1.2.

### Claim 12 (depends on 1)

The process as claimed in claim 1, in which the molar ratio of N-methylglucamine to formaldehyde is 1:1.01 to 1:1.08.

### Claim 13 (depends on 1)

The process as claimed in claim 1, wherein the residual N-methylglucamine content is <1 wt %.

### Claim 14 (depends on 1)

The process as claimed in claim 1, wherein the residual N-methylglucamine content is <0.25 wt %.

### Claim 15 (depends on 1)

The process as claimed in claim 1, wherein the hydrogenation is carried out at 40-50° C.