DEP0010276MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Date of registration: August 12, 1953 Published on June 21, 1956

GERMAN PATENT OFFICE

The invention relates to the use of emulsifiers in the polymerization of butadiene-1, 3, and acrylonitrile at temperatures below 30 ⁰ with the aid of a water-soluble Persulfatkatalysators as well as of a likewise water-soluble iron (II) promoter.

The potash soaps of naturally occurring fatty acids are known as emulsifying substances in the emulsion polymerization of 1,3-butadiene and acrylonitrile by cheapness and easy handling. In addition, potash soaps seem to be the natural fatty acids To increase the effectiveness of the iron (II) promoter and thus increase the conversion yield. However, their use has the disadvantage that they are necessary for the precipitation of the rubber Acidify the excess amounts of soap or fatty acid become water-insoluble with the polymer fail and in this way get into the rubber as impurities. The is very unfavorable in that such inclusions cause an increase in water absorption and a reduction in the usefulness of the polymer for electrical purposes will. In addition, the fatty acids are likely to contribute Use of the polymer in fuel tanks

609 5 * 6/517

P 10276 IVbI 39 c

Tern extracted from the rubber ', leading to the formation of sticky, resinous contaminants leads in fuel.

Unfortunately, it has been found that by reducing the amount of soap added, the

- can avoid excess when acidifying, but at the same time the effectiveness of the soap as an emulsifier as well as their beneficial influence on the promoter in whole or for the most part

ίο picks up. Because of these disadvantages, soaps of natural fatty acids are not particularly useful as emulsifying substances. Instead, cheap, synthetic emulsifiers are often used, which remain water-soluble when acidified. Such synthetic emulsifiers work _; -but -only at. a reaction temperature of 30 ?. or above, good and are uneconomical at temperatures well below ■. In addition, the synthetic emulsifiers do not appear to have the same activating effect on the promoter as soaps made from natural fatty acids.

The invention has the task of cheap and easy to create to-use emulsifiers which provide below 30 ⁰ good polymerization without deposit significant amounts of precipitation on acidification.

The invention is based on the discovery that a mixture of a water-soluble synthetic Emulsifier, and palmitic or stearic potassium shows a synergistic effect.

As above in connection with the natural

'fen has been generally said to have small amounts of palmitic or stearic potassium, which does not have any significant soap deposits cause neither an emulsifier effect nor an influence on the promoter. However, if a such a small amount of palmitic or stearic potassium in conjunction with a larger one Amount of a synthetic emulsifier is used, all three advantages are combined (namely one Avoidance of significant soap precipitation, effective emulsification of the reaction mixture and an increase in the speed of reaction by activating the promoter).

Erfmdungsgemäß described the copolymerization is carried out in the presence of an emulsifier, which odeij for the greater part from a water-soluble upon acidification lasting synthesis tables emulsifier, and a minor portion of _{Kaliumpälmitat:} composed stearate.

■ ..: The combined emulsifier is generally used in a ratio of at least 3 parts per 100 parts of polymeric material (all figures are parts by weight). The ratio of potassium palmitate to polymer is also

, -. _; in parts by weight · 0.3: 100, that of potassium stearate 0.1: 100. The relative maximum amount of potassium palmate or stearate must barely cause any noticeable precipitation and is approximately

:2 parts. ■ - _{) V} , ;;.

.. 'Any emulsifier can be used, provided that it is'water-soluble'. A useful type of emulsifier are the sulfonated FeWaIkOhCiIe ₁ , with their derivatives. · ■■ - ■ · ■ ·

Potassium pelmitate or stearate can be used alone or mixed with the other be, d. H. in the form of commercially available soap, which usually contains both compounds.

70 Example ι,

The basic approach for normal butadiene-acrylonitrile copolymerization reactions is:

1.3-butadiene 64.0 parts by weight

Acrylonitrile 36.0

Water 250.0

Fe SO ₄ · 7 H ₂ Ο ·. ^: 0,278

Mixed tertiary

Mercaptans 0.700

KOH 0.140

; fatty acid potash soaps 5.00

. A mixture thus composed was allowed to copolymerize at 5 ° for 20 hours. After this time had elapsed, the polymerization was terminated by adding 0.200 parts of hydroquinone (as a 5% solution). A 48% conversion had been achieved. If the 5 parts of fatty acid potassium soap were left out in the batch and a synthetic emulsifier composed of 4 parts of a mixed alkylated naphthalenesulfonate, which was condensed with formaldehyde, and ι part of alkyl aryl sodium sulfonate were added in its place, the amount was added a 2ostündigen polymerization at 5 ⁰ conversion reached 5%. One related something less potassium hydroxide, and keep Although 0.100 parts to the _pH value constant. The lower yield when using synthetic emulsifiers instead of fatty acid potassium soaps shows that such a substitute appears very unsatisfactory without regard to the quality of the product. However, if you use a mixture, the majority of which is a synthetic one. If the emulsifier consists and only a small part of fatty acid, then obviously better results are obtained, and the yield is significantly increased, as will be shown in the further examples.

Example 2

The basic approach described in Example 1 was tried out in a series of experiments, which was changed to the extent that the 5 parts of fatty acid potassium soap were omitted and instead an emulsifier mixture, namely 3 parts of the above-mentioned mixed alkylated, formaldehyde-condensed naphthalenesulfonate and ι part of the emulsifier listed in the table was added. Were stirred the monomeric substances, a viscosity regulator and the Emulgatorsubstanzen with addition of KOH to adjust the p _H -value to an alkaline solution, and then dissolved the reaction by adding first

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P 10276 IVb / 39c

from K ₂ S ₄ O ₈ and then from FeSO ₄ · 7H ₂ O. In all cases, the batch polymerized for 17 hours at 5 °. The percentage of the conversion achieved in each case can be found in Table I.

Table I.

% Conversion

Potassium caprylate-caprylic acid 35.4

Potassium laurate, 40.6

Potassium myristate 42.2

Potassium palmitate; 81.5

Potassium stearate 84.9

Potassium Oleate 43.6

Potassium linoleate 16.0

Fatty acid potash soap (commercially available

Mixture) 60.4

Sodium Lauryl Sulphate. 1.1

Alkyl sulfonate 23.3

Alkyl aryl sodium sulfonate 1,2

The significant benefit of using potassium palmitate or potassium stearate or commercially available mixtures thereof can be obtained is obvious. Equivalent amounts of Soaps with other fatty acids show much less favorable results.

The amount of potassium palmitate or stearate used can be within certain limits can be varied to meet the requirements of the desired product or intended Requires reaction. The following examples serve to demonstrate the effect of a reduction the amount of soap below the 1 part used in Example 2.

Example 3

Using the basic approach and procedure described in Example 2 were the experiments repeated, with the various amounts of fatty acid soaps used as described became. The mixtures polymerized for hours at 5 °. Which achieved in any case percent conversion is reported in Table II.

Table II

0.40

I °, ⁶ ° I

Weight percent

0.80

Potassium caprylate caprylic acid ...

Potassium laurate

Potassium myristate

Potassium palmitate

Potassium stearate

fatty acid potash soap (commercially available)

The only difference between the two groups of commercially available fatty acid soaps is the type of existing dispersant. In the latter case, a dispersant was used which Contained considerable amounts of the sodium salt. It is known that sodium groups increase the yield reduce the conversion.

Claims (5)

PATENT CLAIMS: -1. Process for the emulsion copolymerization of butadiene- ^{1,3 and acrylonitrile below 30 0} with a water-soluble persulfate catalyst and a water-soluble iron (II) promoter, characterized by the use of an emulsifier mixture, which for the most part consists of a synthetic emulsifier which remains water-soluble when acidified and is composed to a minor extent of potassium palmitate or potassium stearate. 46.8
4.6
5> o
3.3 69.6
3.6
0.8 44.6
57, o
66.0 84.3
92.1
61.6
41.1 35.1
46.6
50.0 78.1
90.0 70.9
45.2 35.5
43.5
51.0
81.7 ■ 9 ^τ 7
82.9 29.2 40.5 42.2 8o, 6
91.1
60.4
49-3 2. The method according to claim 1, characterized in that that the synthetic emulsifier is formed by a sulfonated fatty alcohol. 3. The method according to claim 1, characterized in that that the synthetic emulsifier is formed by a mixed alkylated sulfonate condensed with formaldehyde. 4. The method according to any one of claims 1 to 3, characterized in that the smaller amount of the emulsifier by potassium palmitate in a proportion of at least 0.3 parts by weight per 100 parts of the polymer Material is formed. 5. The method according to any one of claims 1 to 3, characterized in that the smaller amount of the emulsifier is potassium stearate in a proportion of at least 0.1 part by weight per 100 parts of the polymer Material is formed.