DE1090664B - Method for stabilizing 1-vinyl-pyrrolidone- (2) - Google Patents

Description

GERMAN

The invention relates to a method for stabilizing 1-vinyl-pyrrolidone- (2).

Freshly distilled 1-vinylpyrrolidone- (2) must either used immediately, refrigerated, or stabilized to prevent polymerization. The polymerization is shown by an increase in the viscosity of the monomer, by gel formation or by the formation of a hard solid polymer during storage or shipping. So are samples of freshly distilled l-vinyl-pyrrolidon- (2), which are kept in transparent containers, by simply storing them for a long time Room temperature more and more viscous until a hard, solid polymer is formed. The inclination of 1-vinyl-pyrrolidone- (2) for the polymerization is by slightly elevated temperatures or by temperatures that are at the Distillation of crude 1-vinylpyrrolidone- ^) for production of a pure monomer can be used. So are z. B. in distillation vessels in which l-vinyl-pyrrolidone- (2) for a long time distilled at elevated temperatures, residues of polymers. For those who have been known for a long time Monomers such as styrene, α-methylstyrene, vinyl acetate, Acrylic esters and other unsaturated compounds are used as stabilizers for compounds containing nitro, nitroso, Containing quinone, phenol, oxy or amino groups, is used.

However, many of these compounds are relatively ineffective as stabilizers for 1-vinyl-pyrrolodine- (2). So are z. B. ammonia and amines, which serve as known stabilizers for monomers, activators for the Polymerization of l-vinyl-pyrrolidone- (2) and were used to produce l-vinyl-pyrrolidone- (2) polymers used. Oxy compounds, such as methyl and butyl alcohol, are ineffective as stabilizers, and methylene blue and chloranil discolor the monomer. In addition, many of the soluble stabilizers are difficult to use to remove from the monomers.

According to the invention it has now been found that alkali metal hydroxides, mixtures thereof or mixtures / ₀ added alkali metal carbonates, alkali metal alcoholates and alkali metal sulfides thereof, with sulfur, in amounts of 0.001 to 5 ° to the 1-vinylpyrrolidone (2) polymerization of the 1 -Vinylpyrrolidon- (2 ) effectively prevent at room temperature or elevated temperatures and are much more effective than the stabilizers previously used for monomeric vinyl compounds.

To carry out the process according to the invention, 0.001 to 5%, preferably 0.01 to 1%, of the stabilizers mentioned are added to freshly distilled l-vinyl-pyrrolidone- (2) in a container and the container is closed. In addition, 0.001 to 5 ° / ₀ , preferably 0.01 to 1.0 ° / ₀ , of the various stabilizers can be added to the crude or not yet completely pure 1-vinyl-pyrrolidone- (2) before the distillation, in order to achieve a process for Stabilize
of 1-vinyl-pyrrolidone- (2)

Applicant:

General Aniline & Film Corporation,
New York, NY (V. St. A.)

Representative: Dr. W. Schalk, Dipl.-Ing. P. Wirth,

Dipl.-Ing. G. E. M. Dannenberg

and Dr. V. Schmied-Kowarzik, patent attorneys,

Frankfurt / M, Große Eschenheimer Str. 39

Claimed priority:
V. St. v. America from. June 11, 1956

Charles Peter Albus and George Green Stoner,

Easton, Pa. (V. St. A.),
have been named as inventors

to obtain pure monomer and a polymerization in the distillation device during the distillation to prevent.

The stabilized l-vinyl-pyrrolidone- (2) can either be distilled, decanted or filtered to get this to remove practically insoluble stabilizers from the monomer before it is used for polymerizations will. An advantage of the stabilizers according to the invention for l-vinyl-pyrrolidone- (2) is that they are in are practically insoluble in the monomer and by simply decanting or filtering from the monomer can be removed before its polymerization, while monomers containing soluble stabilizers always need to be distilled.

The following examples illustrate the method of the invention.

The effect of various stabilizers on the polymerization of 1-vinylpyrrolidone- (2) has been through Viscosity measurements (Gardner-Holdt viscosity) of the individual test samples determined.

example 1

A freshly distilled l-vinyl-pyrrolidone- (2) at 50 mm pressure and 125 ° C was used for the stabilization tests. used with the following analytical data:

009 627/404

1-vinyl-pyrrolidone- (2),% 99.5

Polymer,% none

Aldehyde (as acetaldehyde),% ··· ■ 0.003

»F 1.5103

Freezing point 12.54 ⁰ C

Water clear color

Viscosity at 20 ⁰ C ......: ....... less than 14cP

The samples for the experiments were prepared by adding 20 ecm (20 g) of the l-vinyl-pyrrolidone- (2) each 0.05 g of the stabilizer was added. In cases where sulfur is used with other stabilizers became 0.03 g of sulfur and 0.02 g of the other

Stabilizer weighed separately and added to the monomer. The sealed samples were stored in an oven at 70 ^{° C. with circulating air.} They were cooled to room temperature at certain time intervals and returned to the oven after the viscosity determinations.

The results of these tests are shown in Table 1. It can be seen that the invention Stabilizers for l-vinyl-pyrrolidone- (2), such as sodium methylate, sodium hydroxide and sodium sulfide, the for Vinyl compounds are superior to known soluble stabilizers such as sulfur and thiourea.

Table 1

Effect of various stabilizers in a concentration of 0.25 ° / ₀ to the polymerization of

l-vinyl-pyrrolidone- (2) at 7O ⁰ C

stabilizer 0 Days
1 1 2 <r "14
<r ^ "i 4
- <r "1.4
<ü * 14
<Ti4
<c! * 3.4 3
V 4th
iskositä Weeks
1 I 2
fc (centipoise) 175
<^ "\ 4-
"^" 14
<^ * "\ 4- at 20 ° C. _ ^ - * "j ^ _-
^ - ^ "j ^ l 14th Mon
3 ate
4th 14th 5 1. l-vinyl-pyrrolidone- (2) (control) ..
2. Sodium methylate <^ "\ 4
<^ ~ 14 *
<r * ^ * i 4
<f ^ "l 4 <^ "\ 4
«^^ 14
<^ * 14-
<c-14
<r ^ 14-
* c * 1.4
<^ * 14 32
<^ * 14
<^ "14
<^ "\ 4
<r ** 14
<"'* 14
* £ ^ "14
^ * ~ "\ A. 75
<'^ 14
<^ * 14
<if \ 4 125
<τ ^ Ί 4
<^ ** 14 <^ * 14-
4500 Hard <^ 14-
40000 <^ "\ 4-
<r * "l 4- Polymer 275 3. Sodium hydroxide <^ ~ "\ 4-
14th ■ ^ * '14 ·
425 14th <ίΊ4
"<γ14 4. Sodium sulfide ^ »-" ί j / t
<^ ** "l 4- <! * "\ 4 ·
<r "*" i 4- 75 14th 5. Thiourea $ 14 1200 6. Sulfur ■ «ί" "" 14-
<^ "\ 4 7 ³ J ₅ sulfuric _^2/5 sodium
8 ³ I ₅ sulfuric _^2/5 sodium sulfide ..

Example 2 0.25% of the various stabilizers on 1-vinyl

There have been attempts listed in Table 2 pyrrolidone (2) aufzuausgeführt during storage at 70 ⁰ C to the stabilizing effect of 0.02 to show.

Table 2

Effect of the various stabilizers in concentrations of 0.02, 0.05, 0.1 and 0.25% on the polymerization

of l-vinyl-pyrrolidone- (2) at 70 ^° C.

stabilizer

ο 1 Days
2 3 4th
Viscous Weeks
1 I 2
ität (Centipoisei 175
<^ "\ 4 1
ι) at 20 ° C months
2 I 3 | 325 14th
<^ "14 · 25th
<** "\ 4- 45
_< ^ "\ Λ. 60
<^ 14- 90
- ^ * 14- 100
- · ■ "· ί ^ i <^ ** 14
-C * 14
<ίΊ4
15000
<^ ~ "\ 4 250
<^ ** 14 300
<^ "\ 4 ■ <** "Ί 4
450
60000
«Ϋ ^ 14 <^ "\ 4 ·
<c - * \ 4
<^ "\ 4"
_< ^ "\ Λ. <^ "ί 4-
<ί ^ "14 ·
<^ "" \ 4 ·
<^ 14-
<^ "\ 4 · <f Ί 4-
<τ * 14
200
<^ "(4 · <τ ^ * Ί 4-
■ <* Ί4
■ <τΊ4
1800 <r ^ * 14-
<r ^ "14-
6300
<γ ^ "Ι 4- 10,000
<^ "14 <* ^ 14
<^ "\ 4
<^ "\ 4
7000 <τ ^ "ί 4
<"*""14
25,000
<τ ^ 14 <f \ 4
■ β ^ "14
■ <? * "\ 4
35000
- ^ * ί ^ t <^ "ί 4-
jelly <^ "\ 4-
_ ^ "\ A
<^ " 14-
<τ ^ * 14- <^ "\ 4 ·
<^ "\ 4-
<^ "\ 4- <! ^ * 14-
<^ "\ 4 ·
<τ * "ί 4-
■ «^" 14 ·
■ <^ "14- <^ * 14
<γΊ4
90 <^ * 14-
_< - ^ 'Λ Δ.
600
<^ "\ 4 · 2000 ■ <* ^ 14
<^ ** 14
■ <£ ^ * 14
900 ■ ^ * '14
<? * "\ 4
jelly <τ * "14
<ϋ! * 1-4
<i * 14
jelly 2000 <^ "\ / | '
<^ * 14- <^ "\ 4
■ <^ Ί 4-
<^ "\ 4- <^ * 14 *
<! ^ * 14-
■ <'*'"j ^ l <^ * 14-
<τ ** 14 <^ "\ 4-
<τ * 14
■ <^ 14
■ <f ^ 14- <ζ * "\ 4
<^ * 14
125 <τΊ4
<γ * 14
<ίΊ.4 ■ <τ * "14
<^ "\ 4
1500 1800 40 <^ "\ 4 ·
<τ ^ "14-
<Γ ^ * Ι 4- <τ ^ "(4-
<r "14
■ <γ "14 <cl4
<ί * 14
<^ "\ 4- <τ ^ Ί 4-
<γΊ4
<ϋ * 14 - ^ ί λ
• e ^ 'i 4-
<^ "14 <τ * '"14
<'"* ί ^ i
<^ "\ 4 <^ "\ 4
<^ ** 14
<τ ^ "14
<ί "** 14 <^ "\ 4
<τ ^ 14
14th

1.l-vinyl-pyrrolidone- (2) (control)

0.02% stabilizer

2. Sodium methylate ... ■ 3. Sodium hydroxide ...

4. Sodium sulfide

5. Thiourea

6. Pyrogallol

0.05% stabilizer

7. Sodium methylate ...

8. Sodium Hydroxide ...

9. Sodium sulfide

• 10. Thiourea

11. Pyrogallol

0.1% stabilizer

12. Sodium methylate .... 13. Sodium hydroxide ...

14. Sodium sulfide

. 15. Thiourea

16. Pyrogallol

0.25% stabilizer

17. Sodium methylate ...

18. Sodium hydroxide ...

19. Thiourea

20. Pyrogallol

1400

14 jelly

14 2500

Claims (1)

5 6 It was freshly described in Example 1. The thiourea-containing sample also possessed distilled l-vinyl-pyrrolidone- (2) in samples of 50 or an increased viscosity of 125 cP. The sample that 40 ecm used. Containing sodium carbonate showed no increase in From the results given in Table 2, viscosity. it is found that sodium methylate, sodium hydroxide 5 Example 4
and sodium sulfide more effective stabilizers for 1-vinyl pyrrolidon- (2) are than those for vinyl compounds. Samples of 400 g each of l-vinyl-pyrrolidon- (2) were used known soluble stabilizers, such as thiourea per 0.4 g of sodium methylate, sodium hydroxide or and pyrogallol. Sodium sulfide and this for 1 hour at room • D · · ς ¹⁰ shaken temperature. The samples were then at Example ό _{70 to 71} o _C distilled at 2 mm pressure and a clear, A pure 1-vinyl-pyrrolidone- (2) water-white monomer with the refractive index was used for the tests used with the following analytical data: n ^z i = 1.5110 to 1.5111 obtained. In no case was l-vinyl-pyrrolidone (2) ° / 98 0 ^{even the erin} g § ^ste signs of polymerization in Polymer,% ..... '.' .. none of ^the distillation device to be seen. Water,% 0.002 Claim: n ² i 1.5101 ",. "..,,, .., .., P ₃₁ Tj ₆ light yellow Use of alkali hydroxides, alkali carbon Viscosity at 2O ⁰ C '.'. '.'. '.'. '.'. '.'. '.'. '. less than 14cP ^ ^ate ? · AlkaUalkoholaten und AlkaUsulfiden, their ao mixtures or mixtures of the same with sulfur To samples of 30 cc (30 g) of the monomers were added in amounts of 0.001 to 5 ° / ₀ for stabilizing 0.03 g sodium carbonate or thiourea (as ver l-vinyl-pyrrolidone- (2). same substance) given. The sealed samples including a control sample that does not contain a stabilizer. contained, were placed in a circulating air oven at 7O ⁰ C 25 USA. Patent No. 2,136,334. given. After 3 months of storage at 70 ° C, Boundy and Boyer, Styrene, its Polymers, Copoly- the control sample, a viscosity of 125 cP (2O ⁰ C) mers and Derivatives, 1952, page 260/261; certainly. Reppe, Polyvinylpyrrolidone, 1954, p. 13. © 009 627/404 10.60