DE2148185B2 - - Google Patents

Description

wherein R is alkyl radicals having 1 to 4 carbon atoms, τι 1, 2 or 3 and m 1 or 2 and
B) 90 to 10 parts by weight of p-alkoxyphenol of the general formula

RO—

wherein R 'represents an alkyl radical having 1 to 4 carbon atoms.

2. Polymerization inhibitor according to claim 1, characterized by a mixture containing the components A and B in a ratio of 30:70 to 70:30.

3. Use of a polymerization inhibitor according to claim 1 and 2 in an amount of 0.001 to 0.1 percent by weight, preferably 0.03 to 0.06 percent by weight, based on the monomer.

4. Polymerization inhibitor according to claim 1 to 3, characterized in that the mixture from components A and B in a saturated or unsaturated chlorinated hydrocarbon, the 1 or 2 carbon atoms is dissolved.

can be new (German Auslegeschrift 1243172). These mixtures also have the disadvantage that vinyl esters, such as acrylic acid esters or Vinyl acetate, can be split by ammonia.

Mixtures of biobisphenols and / or ripbenylamines and / or pbenazraen with tetralin (French patent 1557 427) has been used as a stabilizer, but the provided Often the demands are not sufficient. So both

Q, for example, polymers colored as a result of the dye content obtain.

It has now been used as a polymerization inhibitor polymerizable vinylgrappen-containing aliphatic, aromatic and heterocyclic compounds found,

s which is characterized by a mixture consisting of the end

A) 10 to 90 parts by weight of thiobisphenol of the general formula

ΊΙ

R _n

\ x

Marg

in which R is alkyl radicals having 1 to 4 carbon atoms, = 1, 2 or 3 and m - 1 or 2, and B) 90 to 10 parts by weight of p-alkoxyphenol of the general formula

RO

-OH

It is known that the premature polymerization of polymerizable compounds, for example during storage or transport, possibly also during the manufacture of the corresponding Monomers, an undesirable phenomenon.

Rubber or resin-like products can result from exposure to air, light, temperature and various impurities are caused on the monomer. The monomer will therefore usually by adding certain polymerization inhibitors to prevent such prepolymerization stabilized. The stabilizing agent should be as soluble as possible in the monomer in order to ensure uniformity Ensure distribution.

A well-known stabilizing agent is phenol (German Auslegeschrift 1 215 134). This polymerization inhibitor has the disadvantage that it is poorly soluble in the monomer and, moreover, its stabilizing effect is severely impaired in the presence of iron or iron compounds. When using p-methoxyphenol (German Auslegeschrift 1 197 445), the effectiveness of the stabilizer in the presence of iron compounds is greatly reduced. This also applies to the known mixtures of p-methoxyphenol and ammonia, which are used to stabilize vinylidene chloride in which R 'represents an alkyl radical having 1 to 4 carbon atoms.
The mixture according to the invention, with which the stabilization of monomers containing vinyl groups against undesired polymerization is considerably improved, shows a strongly synergistic effect which is retained even in the presence of iron or iron compounds.

It has proven to be expedient if the synergistic mixture according to the invention includes the aforementioned Components A and B preferably in a ratio of 30:70 to 70:30. The polymerization inhibitor is used in an amount of 0.001 to 0.1 percent by weight, preferably 0.03 to 0.06 percent by weight, based on the monomer used.

As thiobisphenols, for example, di- (t-butyl-p-cresol) monosulfide, Di- (m-cresol) monosulfide, di-thymol monosulfide, di- (p-t-butyl-catechol) monosulfide and di-carvacrolmonor.ulfide can be used.

Suitable p-alkoxyphenols are p-ethoxy and p-Methoxypheno !, with p-Methoxyphenol being preferred.

The mixture is added to the monomers in bulk, but can also be used to mediate solubility in Chlorinated hydrocarbons are metered in in solution. For this purpose, the mixture is made up of the components A and B, preferably in a saturated or unsaturated chlorohydrocarbon, the 1 or Contains 2 carbon atoms, dissolved.

The mixture according to the invention for preventing undesired polymerization is used with polymerizable vinyl group-containing aliphatics, aromatics and heterocycles.

Aliphatics containing vinyl groups may be mentioned: vinylidene halides, such as vinylidene chloride or bromide and fluoride; Vinyl esters of inorganic acids,

hydroic acid such as vinyl chloride, vinyl bromide, acrylonitrile and methacrylonitrile; Vinyl esters of monocarboxylic acids such as vinyl acetate, vinyl butyrate, vinyl propionate, vinyl 2-ethylhexoate, vinyl usotridecanoic acid esters, vinyl chloroacetate, vinyl valerate and vinyl caproate; Vinyl esters of polybasic carboxylic acids such as divinyl succinate, divinyl adipate, vinyl methallyl pimelate and vinyl methyl glutarate; Vinyl esters of unsaturated acids such as vinyl acrylate, vinyl crotonate and vinyl methacrylate; Vinyl ethers, such as vinyl ethyl ether, vinyl butyl ether and vinyl allyl ether; Vinyl ketones such as vinyl butyl ketone and vinyl ethyl ketone; Allyl derivatives, such as allyl acetate, ahyibutyrate, diallyladipate, methadylpropionate, allyl chloride, methallyl chloride, alyl acrylate, methallyl methacrylate; conjugated polyenes such as butadiene and chloroprene; Ethylenically unsaturated carboxylic and dicarboxylic acids, and their anhydrides and esters, e.g. B. acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, crotonic acid, unsaturated aldehydes such as acrolein, methacrolein and ethacrolein.

Suitable aromatic compounds containing vinyl groups are styrene and its derivatives, such as ethylene-a-methylstyro !, Dichlorostyrene, divinylbenzene, vinylphenol, trivinylbenzene; Vinyl naphthalene, divinyhmphthalin and vinyl diphenyl.

Vinylimidazole and vinylpyridines, for example, can be used as heterocycles containing vinyl groups will.

However, the polymerization inhibitor according to the invention is preferably used in the case of vinyl chloride, Vinylidene chloride and vinyl acetate as well as mixtures of these monomers.

The synergistic mixture is particularly advantageous in stabilizing moist crude vinyl chloride the end. This according to the classical synthesis from hydrogen chloride and acetylene or by Dehydrochlorination of 1,2-dichloroethane, produced must usually be washed with dilute lye for the purpose of neutralization and placed in a dewatering column be dewatered azeotropically, at the same time any low boilers present are separated off. It is now known that moist crude vinyl chloride is particularly prone to polymerization, which means in the azeotropic dewatering of the crude vinyl chloride columns made of stainless steel but in particular those made of Iron can be laid with polymer. By using the stabilizer mixture according to the invention The polymerisation of the column bottom and lines of the distillation plant is also carried out Avoided at higher temperatures and in the presence of iron. Thus, relatively cheap distillation systems can be used made of iron, which usually takes a short time when using conventional stabilizers Time had to be cleaned in a costly manner, operated over long periods of time without cleaning will.

The mode of action of the polymerization inhibitor according to the invention results from the following Try.

example 1

500 g of vinyl chloride are according to the block polymerization along with 0.5 g Azodiisobuttersäurettitril and in the presence of 0.05 g of polymerization below about 10 hours at 70 ⁰ C Einesi polymerized in a stirred autoclave. The yield of polyvinyl chloride without the addition of a polymerization inhibitor is assumed to be 100 percent by weight. The following yields result for the stabilizers mentioned below.

Table la (effect of the invention Polymerization notifiers)

to

Polymerization inhibitor Conc
tration
On weight
percent
related to
vinyl
chloride) yield
Polyvinyl
cUorid
in weight
percent 2,2'-thiobis- (4-methyl-,
6-t-butylphenol) \
p-methoxyphenol. ...
2,2'-thiobis- (3-methyl-
4-propyl-6-t-butylphenol)
pn-butoxyphenol
6,6'-thiobis (4-methyl-
catechol)
p-Athoxyphenol 0.025 \
0.025 y
0.025 \
0.025 y
0.025 \
0.025 y 21
26th
22nd

Table 1 b (comparative tests)

Polymerization inhibitor Conc yield tration Polyvinyl 30th (in weight chloride percent in weight Without addition related to percent p-methoxyphenol vinyl p-methoxyphenol chloride) 100 ammonia 0 46 2,2'-thiobis (4-methyl- 0.05 AA 6-t-butylphenol) 0.025 \ 'T ⁴ T 2,2'-thiobis (4-methyl- 0.025 j 6-t-butylphenol) 50 Tetralin 0.Λ5 2,2'-thiobis (4-methyl- 67 6-t-bulylphenol) 0.025 \ O / Diphenylamine 0.025 y Indulin Tetralin 0.0125 ί ₅₀ 2,2'-thiobis (4-methyl- 0.0125 I. 6-t-butylphenol) 0.0125 [ Indulin 1 equal parts 0.0125 J. Tetralin J overall 2,2'-thiobis (3-methyl- 40 4-propyl-6-t-butylphenol) 0.05 ³⁵ 6,6'-thiobis (4-methyl- catechol) 55 0.05 52 0.05

Table 1 a, in which the polymerization inhibitors according to the invention are used as stabilizers show the superiority over the tests listed for comparison (Table Ib) of the mixtures according to the invention.

Example 2

As in Example 1, the experiments are repeated in the presence of 1 g of iron powder / rust mixture (1: 1).
Table 2 a shows the results with the inventive

2 148 165 5 *

moderate polymerization inhibitors, while weight pressure is assumed. For the below belle 2b the results with the comparators mentioned "StaWhsienragsramei" result in the following

erä
Exploit:

Table 2a

Polymerisation inhibitor Conc
tration
Gn weight
percent
related to
vinyl
chloride) yield
Polyvinyl
chloride
In weight
percent 2 _r 2'-thiobis (4-methyl-
6-t-butylphenol)
p-methoxyphenol
2 ^ '- thiobis- (3-methyI-
4-pr.opyI-6-t-bntylphenoI)
pn-butoxyphenol
6,6'-thiobis (4-methyl-
catechin)
p-Athoxyphenol 0.025 1
0.025 /
0.025 \
0.025 y
0.025 1
0.025 y 23
25th
23

Table 3 a (Effect of the ecnndong following Polymerization inhibitor)

Polymerization inhibitor

Table 2b Conc yield tration Polyvinyl (in weight chloride percent in weight Polymerization inhibitor related to percent vinyl chloride 75 0.05 11 p-methoxyphenol 0.025 \ 73 p-methoxyphenol 0.025 y ammonia 60 2,2'-thiobis (4-methyl- 0.05 6-t-butylphenol) 2,2'-thiobis (4-methyl- 0.025 \ OS 6-t-butylphenol) 0 025 y Tetralin. . ... 2,2'-thiobis (4-methyl- 0.0125 ) cc 6-t-butylphenol) 0.0125 55 Diphenylamine 0.0125 [ Indulin 0.0125 J. Tetralin 2,2'-thiobis (4-methyl- 50 6-t-butylphenol) 0.05 Indulic \ same parts Tetralin J overall 60 2,2'-thiobis (3-methyl- 0.05 4-propyl-6-t-butylphenol) 58 6,6'-thiobis- (4-metItyl- 0.05 catechol)

2 ^ '- thiobis- (4-metbyl-

6-t-bu ^ lphenol)

p-MethoxypheaoI

ao 2 ^ '- thiobis- (3-nieth.yl-

4-p ^r opyl-6-t-butylphenoI)

p-n-3utoxyphenol

6,6'-thiobis (4-methyl-

catechol)

as p-ethoxyphenoI

The results of Table 2a show that the mixtures according to the invention also in the presence of Iron and iron compounds are fully effective.

Example 3

Instead of the block polymerization carried out in Examples 1 and 2, the polymerization inhibitors according to the invention are tested in the context of a suspension polymerisation.

500 g of vinyl chloride are polymerized together with 0.5 g of azodiisobutyric acid and in the presence of 0.05 g of one of the polymerization inhibitors listed below for 10 hours at 70 ° C. in a stirred autoclave. The yield of polyvinyl chloride without the addition of a polymerization inhibitor is expressed as 100 % concentration on percent by weight, based on

Vinyl chloride)

0.025 \ 0.025 /

0.025 0.025 /

0.025 \ 0.025 /

Yield of polyvinyl chloride in percent by weight

19th

25 21

Table 3 b (comparative tests)

Polymerization inhibitor Without addition

p-methoxyphenol

♦ ° p-methoxyphenol

ammonia

2,2'-thiobis (4-methyl-

6-t-butylphenol)

2,2'-thiobis (4-methyl-

♦ 5 6-t-butylphenol)

Tetralin

2,2'-thiobis (4-methyl-6-t-butylphenol) .......

Diphenylamine

Indulin

Tetralin

2,2'-thiobis (4-methyl-

6-t-butylphenol) Indulin 1 equal parts Tetralin J overall 2,2'-thiobis (3-methyl-

4-propy) -6-t-butylphenol) 6,6'-thiobis- (4-methyl-

brenzkaicchin)

Concentration (in percent by weight based on vinyl chloride)

0.05 0.025 \ 0.025 /

0.05

0.025 \ 0.025 /

0.0125 0.0125 0.0125 0.0125

0.05

0.05 0.05

Yield of polyvinyl chloride in percent by weight

100 44

43 50 68

41

40

54 33

The suspension polymerization is carried out according to Example 2 in the presence of 1 g of iron powder rust-6s Performed ingeniously (1: 1). Table 4 a brings the Results with the inhibitors according to the invention during Table 4b tests with comparative materials shows.

Table 4a

Conc yield tration Polyvinyl (in weight chloride Polymerization inhibitor percent in weight related to percent vinyl chloride) 2,2'-thiobis (4-methyl- 6-t-butylphenol) 0.025 1 TO p-methoxyphenol 0.025 I. 2,2 '~' fhiobis- (3-methyl- 4-propyl-6-t-butylphenol) 0.025 1 Zj ρ n-butoxyphenol 0.025 / 6,6'-thiobis (4-methyI- 1 fl catechol) 0.025 \
0.025 y 19th p-ethoxyphenol

Table 5

Polymerization inhibitor Conc
tration
Ppm by weight Period of time
lake. 2,2'-thiobis (4-methyl-
6-t-butylphenol)
p-methoxyphenol
2,2'-thiobis (4-methyl-
¹⁰ 6-t-butylphenol)
p-methoxyphenol
Without addition 100
100
50 1
50 /
0 100
110
150
58

Table 5 shows that when polymerizing vinyl acetate with the addition of the Mixtures according to the invention a strong polymerization inhibition occurs.

Table A b

Conc yield tration Polyvinyl (in weight chloride Polymerization inhibitor percent in weight related to percent vinyl chloride) 75 p-methoxyphenol 0.05 Ί1 p-methoxyphenol 0.025 \ IL ammonia 0.025 y 2,2'-thiobis (4-methyl- 61 6-t-butylphenol) 0.05 2,2'-thiobis (4-methyl- in 6-t-butylphenol) 0.025 \ Tetralin 0.025 y 2,2'-thiobis (4-methyl- 6-t-butylphenol) 0.125 - Diphenylamine 0.125 YY Indulin 0.125 Tetralin 0.125 2,2'-thiobis (4-methyl- 6-t-butylphenol) 48 Indulin \ equal parts Tetralin J overall 2,2'-thiobis- (3-methyl- 62 4-propyl-6-t-butylphenol) 6,6'-thiobis (4-methyl- 0.05 60 catechol) 0.05 0.05

Example 5

100 cm ³ of styrene are dissolved together with 60 mg of benzoyl peroxide slide ₅ in 200 cm ³ of methanol and polymerized for 1 hour at 100 ⁰ C and then filtered off, the resultant polystyrene has a glass filter crucible. If the yield of polystyrene without the addition of a stabilizer is assumed to be 100 percent by weight, the following yields result when the following polymerization inhibitors are added:

Tables 3 a, 3 b, 4a, 4b show the synergistic Effect of the polymerization inhibitor according to the invention. It remains in the presence of iron and iron compounds fully preserved.

Example 4 Table 6

33

40 polymerization inhibitor

Without addition

6,6'-thiobis- (2-ethyl-

resorcinol)

p-propoxyphenol ...
6,6'-thiobis- (2-ethyl-

resorcinol)

p-propoxyphenol ...

Concentration (in percent by weight based on styrene)

0.05 0.05

(.025 \ 1.025 J!

Yield of polystyrene in percent by weight

100

48

54

20th

Table 6 can be seen that when polymerizing styrene with the addition of the invention Mixtures a strong polymerization inhibition occurs.

55

Example 6

20 ml of vinyl acetate each, provided with the stabilizing agents listed below, are mixed with 180 mg dilauroyl peroxide brought to boiling temperature in a special flask, whereupon the external heat supply is set. Due to the heat of polymerization that occurs, the mixture begins after one given time to boil again. The time until the samples boil again is a measure of the quality of the polymerization inhibitor. 15 g of methyl methacrylate are combined dissolved in 90 g of η-hexane with 100 mg of dibenzoyl peroxide and polymerized at 65 ° C. for 24 hours. The resulting Polymer is filtered off from the η-hexane and recorded gravimetrically. Will the polymer yield Assuming 100 percent by weight without the addition of a stabilizer, this results in the addition of the following: Polymerization inhibitors the following yields:

409540/380

Table 7 Conc yield tration Polymer
in weight (in weight
percent percent Polymerization inhibitor related to Monomer) 100 0 Without addition 58 3,3'-thiobis (5-t-butyl- 0.05 49 i) -methyl- hydroquinone) 0.05 p-methoxyphenol 3,3'-thiobis (5-t-butyl- 0.023 \ 21 6-methyl-hydroquinone) 0.025 / p-methoxyphenol

ίο

polymerized at 70 ° C. The polymer produced is filtered off from the solvent and after drying balanced. If the polymer yield without stabilizer is assumed to be 100 percent by weight, the following yields result when the following polymerization inhibitors are added:

Table 8

Polymerization inhibitor

Table 7 can be seen that when polymerizing methyl methacrylate under When the mixtures according to the invention are added, a strong inhibition of polymerization occurs.

Example 7

15 g of 4-vinylpyridine are dissolved with 100 mg of dibenzoyl oxide in 100 cm ^{3 of} η-hexane and taken for 20 hours

Without addition

Di-m-cresol monosulfide

p-ethoxyphenol

Di-m-cresol monosulfide
^ao p-ethoxyphenol

concentration

(in percent by weight based on

Monomer)

0.05

0.05

0.025

0.025

Yield of polymer in percent by weight

100 49 53

19th

Table 8 can be seen that when polymerizing 4-vinylpyridine with the addition of the invention Mixtures a strong polymerization inhibition occurs.

Claims (1)

2148186 Patent claims: J, Polymerization inhibitor for polymerizable vinyl groups containing aliphatic, aromatic and heterocyclic compounds, characterized by a mixture, b ^ tebendaus
A) 10 to 90 weight thiobisphenol of the general formula (HO) , (OH) _n ,