DE1793378C3 - N-acyl-a-aminopercarboxylic acid tert-butyl ester - Google Patents

Description

R ² CH,

U)

10

in which A is a phthalimide or succinimido radical, R ^{1 is} a hydrogen atom, the methyl group or the benzyl group and R ^{2 is} a hydrogen atom or the methyl group

2. Use of the compounds (I) as initiators for the radical polymerization of olefinic unsaturated monomers.

The invention relates to tert-butyl N-acyl-α-aminopercarboxylic acid.

It is well known olefinically unsaturated compounds by the methods of radical Polymerize to polymerize. The usual polymerization initiators for this, e.g. potassium persulfate percarboxylic acids however, or azodiisobutyronitrile often give rise to because of their large activity undesirable side reactions such as chain termination and branching, so that one does not have the properties high molecular weight linear polymer achieved The use of the known initiators is particularly critical in the case of the polymerization or copolymerization of bifunctional monomers, as is also generally the case is known Here, premature crosslinking takes place during the polymerization, which can only be achieved after or want to effect during the shaping in an additional polymerization step.

The invention was therefore based on the object of changing the technology to less active, but nonetheless linear Polymerization does not enrich initiators slowing down.

N-acyl-a-iiminopercarboxylic acid tert-butyl esters of the general type not previously described in the literature have been found Formula I found

R ¹ O

CH ₃

ACOOOC-CH ₃

(1)

R ²

CH,

in which A is a phthalimido or succinimido radical, R ^{1 is} a hydrogen atom, the methyl group or the benzyl group and R ^{2 is} a hydrogen atom or the methyl group.

The N-phthalyl or succinyl-Ä-aminocarboxylic acid tert-butyl esters can be prepared by known methods, e.g. B. by reacting N-phthalyl- or -Succinyl-aaminocarbonsäurehalogeniden with tert-butyl hydroperoxide, preferably in the molecular ratio, advantageously at temperatures from -15 to +10 ⁰ C in the presence of bases such as pyridine and optionally in the presence of inert? R Solvents.

The N-acyl-a-aminopercafboxylic acid tert-butyl ester according to the invention are suitable as initiators for the radical polymerization of olefinically unsaturated Monomers or mixtures thereof by the methods of block, solution, suspension and Emulsion polymerization. Preferred monomers are styrene, acrylonitrile, methacrylonitrile, acrylic acid and theirs Esters, butadiene and substituted butadienes, vinyl esters of carboxylic acids and sulfonic acids, and vinyl ethers. They have proven to be particularly suitable as initiators for emulsion polymerization, since they are added can be converted from acids into the aqueous phase, that is to say either oil-soluble or water-soluble Form or both forms can be used at the same time, so that one can concentrate the Initiators in the aqueous and organic phase and thus the course of the polymerization in a simple manner can regulate. The polymerization is carried out in the amounts customary for the respective types of polymerization carried out on initiators under known conditions

The parts given in the following examples are parts by weight. The parts by weight are related to the Parts of space such as kilograms to liters.

example 1

5.58 parts of N-Phthalylaminoessigsäurechlorid dissolved in 15 parts by volume of methylene chloride are, within 40 minutes at - 10 ⁰ C to a solution of 4.60 parts tert-butyl hydroperoxide and 3.22 parts of 2,6-lutidine in 40 parts by volume of methylene chloride under Stirring is metered in. Stirring is then continued for 2 hours at 0 ° C., after which the reaction mixture is washed neutral by treatment with dilute sulfuric acid and sodium hydrogen carbonate solution. The excess tert-butyl hydroperoxide is removed from the solution, which has been dried with magnesium sulfate, by chromatography on a precooled short aluminum oxide column. After the solvent has been distilled off, 5.95 parts (86% of theory) of tert-butyl N-phthalylaminoperacetate are obtained, which, after recrystallization from a mixture of methylene chloride and petroleum ether, has a melting point of 95 to 97.degree.

Example 2

By reacting 3.56 parts of phthalylalanyl chloride with 1.53 parts of tert-butyl hydroperoxide and 1.35 parts of pyridine according to that described in Example 1 Working method and similar work-up of the reaction mixture gives 2.85 parts (65% of theory)

N-phthalyl-Ä-aminoperpropionsäure tert-butyl ester of melting point 110 to 112 ⁰ C as colorless crystals.

Example 3

According to the procedure described in Example 1, 3.0 parts of N-phthalyl-ji-phenylalanyl chloride are used with 0.79 parts of pyridine and 0.99 parts of tert-butyl hydroperoxide and the reaction mixture works in in an analogous way. 2.30 parts (66% of theory) of N-phthalyl-α-amino-j-phenylperpropionic acid tert-butyl ester are obtained from melting point 112 to 114 ° C.

Example 4

5.0 parts of N-phthalyl-flc-amino-isobutyric acid chloride are dissolved in methylene chloride with 2.3 parts of tert-butyl hydroperoxide and 2.1 parts of pyridine and as in Example 1 described implemented, after which the solution

17 93 37 «

by treating with dilute sulfuric acid Sodium hydrogen carbonate solution is washed neutral. After removing the excess tert-butyl hydroperoxide Petroleum ether is slowly added to the resulting solution on an aluminum oxide column. Man receives 0.25 parts (6% of theory) of a precipitate of N-Phlhalyi-a-amino-isobutyric anhydride from Melting point 167 to 168 ° G. If petroleum ether is added further, a second crystal fraction is obtained. After filtration, 1.51 parts (25% of theory) of N-phthalyl-a-aminoper-isobutyric acid tert-butyl ester are obtained as colorless needles with a melting point of 40 to 50 ° C (decomposition).

Example 5

4.0 parts of succinylglycil chloride are combined with 2.43 parts tert-butyl hydroperoxide and 2.14 parts of pyridine in 35 Parts by volume of methylene chloride reacted as in Example 1, after which the reaction mixture, likewise analogously Example 1, is worked up. 2.75 parts are obtained (53% of theory) N-succinyl-a-aminoperacetic acid tert-butyl ester, after being dissolved twice from a mixture of methylene chloride and petroleum ether has a melting point of 92 to 93 ° C

Example 6

10 parts of styrene are heated to 110 ° C for 10 hours together with 0.01 part of lauroyl peroxide; the Uci rate is 89%. The polymer obtained has a K value (according to Fikentscher, measured as a 0.1% by weight solution in toluene) of 74.5. Use instead Lauroyl peroxide N-Phthalyl-a-aminoper-isobutyric acid tert-butyl ester, the conversion is 94% and the polymer has a K value of 85.

Example 7

160 parts of water are mixed with 1.7 parts of potassium phosphate, 70 parts of a 20% strength by weight aqueous solution of an emulsifier based on dodecyl benzosulfonate and L5 parts of dodecyl mercaptan are added. 175 parts of butadiene, 175 parts of styrene and 10.5 parts of acrylic acid. After adding 1 part of an initiator, the mixture is heated to 62 ° C. for 10 hours heated, the monomers polymerize. The crosslinking of the polymer is determined by the determination the tear strength determined. A low tear strength indicates a low degree of crosslinking.

The following results are achieved using the following initiators:

initiator Tear-resistant speed (kg / cm ² ) Potassium persulfate 24 N-succinyl-a-aminoperacetic acid tert-butyl ester 7.5 N-phthalyl-a-aminoper-isobutyric acid tert-butyl ester 9.0 N-phthalyl-ix-amino-JJ-phenyl- tert-butyl perpropionate 8.5

Example 8

100 parts of a 10% strength by weight solution of 2-cyanobutadiene in dimethylformamide are added polymerized by 0.1 part of initiator for 10 hours at 70 ° C using various initiators The results obtained can be seen from the following table:

initiator

Sales K value Tear resistance Lauroyl peroxide 77% Azodiisobutyronitrile 85%

N-phthalyl-ar-amino-jS-phenylperpropion- 96% acid tert-butyl ester

not measurable, networked
not measurable, networked
79

Test specimen, inhomogeneous test specimen, inhomogeneous 84.5 (kg / cm ² )

Claims (1)

37 "Claims: 1. N-acyl-a-aminopercarboxylic acid tert-butyl ester of the general formula I. R ¹ O CH ₃ A — C — C — O — O — C — CH ₃