# US 10,479,851 B2 · Preparation of N-vinyl carboxamides in a series of reactor units

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- Number: US 10,479,851 B2
- Document ID: US10479851B2
- Status: Granted
- Kind: B2
- Application number: 15/746,462
- Filed: 2016-07-19
- Published: 2018-07-26
- Granted: 2019-11-19
- Earliest claimed: 2015-07-24
- Assignees: Base SE
- Applicants: BASF SE
- Inventors: Christiane Lange; Hugo Vale; Hans-Joachim Haehnle; Oliver Soetje
- Web page: https://patentgrep.com/patent/US10479851B2

## CPC

- C08F 126/02: by a single or double bond to nitrogen
- B01J 19/0066: {Stirrers (mixing per se B01F)}
- B01J 19/1862: {placed in series}
- B01J 19/245: {placed in series}
- C08F 2/01: characterised by special features of the polymerisation apparatus used
- C08F 2/10: Aqueous solvent
- C08F 26/02: by a single or double bond to nitrogen
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

Disclosed herein is a process for producing polymers of an N-vinyl carboxamide, including the steps of flowing a reaction mixture containing an aqueous liquid containing at least one polymerization initiator, N-vinyl carboxamide monomer or a monomer mixture containing N-vinyl carboxamide into a reactor system, and polymerizing the monomer or monomer mixture to produce the polymer of a N-vinyl carboxamide. The polymers resulting therefrom may be hydrolyzed to provide polymers containing vinyl amine units. Also disclosed herein is an apparatus suitable for producing the polymers.

## Claims

### Claim 1

A process for producing a polymer of an N-vinyl carboxamide, the process comprising:
flowing a reaction mixture comprising an aqueous liquid comprising at least one polymerisation initiator, N-vinyl carboxamide monomer or a monomer mixture comprising N-vinyl carboxamide into a reactor system; and
polymerising the monomer or monomer mixture to produce the polymer of N-vinyl carboxamide,
wherein:
the reactor system comprises a series of reactor units comprising a combination of at least one mixed flow reactor and at least one single pass tubular reactor, in which
i) the at least one mixed flow reactor comprises at least one vessel comprising an internal mixer, an external mixer, or both, and
ii) the at least one single pass tubular reactor comprises a tubular section disposed between two ends, at least one inlet and at least one outlet in which the reaction mixture flows through the single pass tubular reactor only once; and
substantially none of the reaction mixture exits the single pass tubular reactor less than 50% of a mean residence time of the reaction mixture in the single pass tubular reactor.

### Claim 2 (depends on 1)

The process of claim 1, wherein the N-vinyl carboxamide is N-vinyl formamide, N-vinyl acetamide, or both.

### Claim 3 (depends on 1)

The process of claim 1, wherein the reactor system comprises:
i) from 1 to 10 mixed flow reactors; and
ii) from 1 to 5 single pass tubular reactors.

### Claim 4 (depends on 1)

The process of claim 1, wherein the at least one single pass tubular reactor is devoid of any internal mixing elements.

### Claim 5 (depends on 1)

The process of claim 1, wherein the at least one mixed flow reactor comprises in series and in sequence a pump, static or dynamic mixer and a tubular vessel.

### Claim 6 (depends on 1)

The process of claim 1, wherein the at least one mixed flow reactor comprises a continuous stirred tank reactor (CSTR).

### Claim 7 (depends on 5)

The process of claim 5, wherein a recycle loop conveys a portion of the reaction mixture exiting the tubular vessel into reaction mixture entering the pump.

### Claim 8 (depends on 1)

The process of claim 1, wherein:
the at least one polymerisation initiator is added to the reaction mixture in at least two places; and
each polymerisation initiator addition is before each at least one mixed flow reactor and each at least one single pass tubular reactor.

### Claim 9 (depends on 1)

The process of claim 1, wherein the reaction mixture is passed through an in-line static or dynamic mixer following the addition of each at least one polymerisation initiator before the so treated reaction mixture flows into each at least one mixed flow reactor and each at least one single pass tubular reactor.

### Claim 10 (depends on 1)

The process of claim 1, wherein the monomer or monomer mixture is polymerised at temperatures ranging from 1 to 120° C.

### Claim 11 (depends on 1)

The process of claim 1, comprising:
a) combining an optionally buffered aqueous liquid and the N-vinyl carboxamide monomer or monomer mixture comprising the N-vinyl carboxamide to form the reaction mixture, and optionally passing the reaction mixture through a static mixer;
b) adding at least one polymerisation initiator into the reaction mixture either i) before feeding the reaction mixture into a first mixed flow reactor, in which the so treated reaction mixture is optionally passed through a static or dynamic mixer before entering said first mixed flow reactor; or ii) into the first mixed flow reactor in step (c);
c) flowing reaction mixture into said first mixed flow reactor in which the monomer or monomer mixture in the reaction mixture polymerises as it passes through said first mixed flow reactor to form a partially polymerised reaction product within the reaction mixture;
d) flowing a portion of the reaction mixture resulting from step (c) in a recycle loop to the reaction mixture prior to entering the first mixed flow reactor and adding further at least one polymerisation initiator to the remainder of the reaction mixture resulting from step (c) either i) before feeding the reaction mixture into a second mixed flow reactor, in which the so treated reaction mixture is optionally passed through a static or dynamic mixer before entering said second mixed flow reactor; or ii) into the second mixed flow reactor in step (e);
e) flowing the reaction mixture resulting from step (d) into a second mixed flow reactor in which the monomer or monomer mixture in the reaction mixture polymerises as it passes through the second mixed flow reactor to form a further polymerised reaction product within the reaction mixture;
f) flowing a portion of the reaction mixture resulting from step (e) in a recycle loop to the reaction mixture prior to entering the second mixed flow reactor and adding further at least one polymerisation initiator to the remainder of the reaction mixture resulting from step (e) either i) before feeding the reaction mixture into at least one single pass tubular reactor, in which the so treated reaction mixture is optionally passed through a static mixer before entering the single pass tubular reactor; or ii) into the at least one single pass tubular reactor in step (g);
g) flowing the remaining reaction mixture of step (0 into the at least one single pass tubular reactor in which remaining monomer or monomer mixture in the reaction mixture polymerises as it passes through the at least one single pass tubular reactor to form the polymer of N-vinyl carboxamide.

### Claim 12 (depends on 1)

The process of claim 1, which is operated continuously.

### Claim 13 (depends on 1)

The process of claim 1, wherein at least 60% by weight of the monomer has been converted to the polymer when the reaction mixture has exited the last at least one mixed flow reactor and before entering the first single pass tubular reactor.

### Claim 14

An apparatus, comprising a reactor system suitable for producing a polymer of a N-vinyl carboxamide by polymerising an N-vinyl carboxamide monomer or a monomer mixture comprising N-vinyl carboxamide contained in an aqueous reaction mixture,
wherein:
the reactor system comprises a series of reactor units comprising a combination of at least one mixed flow reactor and at least one single pass tubular reactor, in which
i) the at least one mixed flow reactor comprises at least one vessel comprising an internal mixer, an external mixer, or both, and
ii) the at least one single pass tubular reactor comprises a tubular section disposed between two ends, at least one inlet and at least one outlet, in which the reactor system is arranged such that reaction mixture flows through the single pass tubular reactor only once; and
the reactor system is provided in such a way that substantially none of the reaction mixture exits the single pass tubular reactor less than 50% of a mean residence time of the reaction mixture in the single pass tubular reactor.