CS258789B1 - N ', N'-bis [3- (3,5-dialkyl-4-hydroxyphenyl) propiono] -thiadialkano dihydrazides and their method of preparation - Google Patents

Abstract

The invention relates to N,N'-bis/3-(3,5-dialkyl-4-hydroxyphenyl)propions/thiodialkane dihydrazides of the general formula I where R1, R2 is alkyl with 1 to 24 carbon atoms and n is 1 to 24. These compounds, which are polymer stabilizers, are prepared by reacting dihydrazides of thiodialkane dicarboxylic acids with esters or halides of (3,5-dialkyl-4-hydroxyphenyl)propionic acid.

Description

The present invention relates to N ', N'-bis / 3- (3,5-dialkyl-4-hydroxyphenyl) propionol-thiodialkanodihydrazes and processes for their preparation.

The problem of reliably securing the stabilization of plastics against thermo-oxidative degradation lies in the right choice of the stabilization system. When selecting it, the different conditions to which the polymer is exposed during processing and during its application must be taken into account. For processing where the heat conditions are the hardest, a synergistic mixture of a low molecular weight phenolic stabilizer with a sulfur or phosphite stabilizer is most suitable. On the other hand, for the long-term thermo-oxidative stability of the final product, where it is most important that the antioxidant act in the polymer for as long as possible, a stabilizer with a higher molecular weight is required which partially provides greater volatility and liquid extraction resistance. Since each type of stabilizer has its own specific function, it is necessary for most polymers to use a stabilizer system consisting of: from multiple components.

Another problem often arises with the presence of trace amounts of catalysts that remain in the polymer after processing and which, despite their low concentration, are non-negligible promoters of oxidative degradation. For their deactivation, an additional stabilizing component must be added to the polymer. In this way, the stabilization system is expanded, requiring higher demands on the dosage control of the individual components in industry. It is also important that the more components of the stabilizing system, the greater the risk of their limited compatibility with the polymer matrix. This may result in an inhomogeneous distribution of the additives in the polymer, which in extreme cases may lead to the stabilization of the stabilizer on the polymer surface. In view of the long-term preservation of the utility properties of the polymer, these facts are undesirable.

It has therefore been attempted to prepare stabilizers containing multiple stabilizing functions in their molecule. For example, phenol and hydrazide-containing stabilizers, e.g., commercial XRGANOX 1,024 N, N'-bis / 3- (3,5-ditBu-4-hydroxyphenyl) propiono / hydrazide, phenol and sulfide-containing stabilizers such as commercial IRGANOX 1,035 - bis / 3- (3,5-ditBu-4-hydroxybenzyl) methyl carboxyethyl / sulfide and phenol- and amino-containing stabilizers such as commercial mauGARD XL-1 - 2,2'-oxamido bis- / ethyl 3- (3,5 (Di-Bu-4-hydroxyphenyl) propionate].

However, each of these compounds contains a maximum of two stabilizing functions. The addition of an additional component is therefore again necessary to extend the stabilizing range.

These disadvantages are overcome with the compounds of the present invention:

The present invention relates to the N ', N'-bis / 3- (3,5-dialkyl-4-hydroxyphenyl) propiono] thiodialcanodihydrazides of formula (I):

where

Rp R1 = alkyl of 1 to 24 carbon atoms n = 1 to 24

The invention further provides a process of formula (A):

^ ^<CH2> IT production dihydrazides of the formula (I) by reaction of compound

NH— NH ₂ (A) 'Wu'

-NH-NH _O where n is 1 to 24 with an acid ester of formula (B)

HO- (CH _{2) 2} OR j -C

R ₂ ^X (B) is as defined above and has 1 to 12 carbon atoms

where

R 1, R ₂ have the above

R 1 is alkyl s at temperatures of 20 to 300 ° C for 0.1 to 10 hours.

The present invention also provides a process for the preparation of dihydrazides of formula (I) by reacting a compound of formula (A) with an acid halide of formula (C);

O. . II (O (ch ₂ ) ₂ -cx where

R 1, R 5 have the above meanings and

X is halogen at temperatures of 0 to 200 ° C for 0.1 to 10 hours wherein the compounds of formula (A) are used either in double molar excess relative to the compound of formula (C) or the reaction is carried out in the presence of an equimolar amount of trialkylamine; pyridine.

N ', N'-bis / 3- (3,5-dialkyl-4-hydroxyphenyl) propiono] -thiodialkanodihydrazides are compounds containing three important stabilizing functions in their molecule. The most important of these is the phenolic function acting in the polymer as a radical scavenger. The sulfur function is characterized by its ability to break down hydroperoxides and can therefore be a good synergist for the phenol present. The last of the three is the acylhydrazide moiety - CO - NH - CO -. Its free electron vapors on nitrogen and oxygen have the ability to coordinate with unoccupied orbits of some metal ions and thus act as an effective deactivator of the traces of catalytic metals in the polymer.

Thus, the presence of all three stabilizing functions in one molecule and molecular weight (from 700 onwards) makes N ', N'-bis / 3- (3,5-dialkyl-4-hydroxyphenyl) propiono-thiodialcanodihydrazide highly effective inhibitors of thermooxidative degradation for polyolefins.

They are effective both in the processing process and in the long-term stabilization of the polymer because, due to their molecular weight, they have partially suppressed volatility and solubility in non-polar hydrocarbons. They are insoluble in water and hexane and dissolve well in toluene or acetone.

The method of preparation may be selected according to the nature of the dialkylhydroxyphenylpropionic acid. For acids which readily form a halide of formula (C), any of the above methods may be used, for acids in which the halogen could react with the phenolic group of the molecule itself. (e.g. 3- (3,5-dimethyl-4-hydroxyphenyl) propionic acid), it is preferable to use only the first method, that is, reacting a compound of formula (A) with an alkyl ester of formula (B). The preparation of the stabilizer in both cases is based on dialkanoic acid dihydrazides (A), a compound which is available by conventional synthetic procedures. E.g. A preparation process is known starting from thiodicarboxylic acid di-thylester, which is converted to the acid dihydrazide by heating at 70 to 120 ° C with hydrazine non-hydrate. The reaction is almost quantitative, forming almost exclusively the monosubstituted hydrazide. The free second nitrogen atom is then suitable for reaction with another substituent. In this case, it is the acyl phenylpropionic acid which is attached here by reaction of its alkyl esters (most often methyl) or halide (most often chloride). Since the reaction of the thiodicarboxylic acid with hydrazine proceeds almost quantitatively, in some cases it is possible to acylate the second hydrazine nitrogen directly in the reaction mixture without having to isolate compound (A). However, this process is not generally feasible and its use depends on the individual nature of the acid used. The reaction of the dihydrazide (A) with the acid ester of formula (B) most often takes place at temperatures around 150 ° C. It is kept under stirring, under a protective nitrogen atmosphere for 3 to 5 hours.

When the acid chloride of formula (C) is used, it is sufficient to merely mix solutions of both components in anhydrous solvent and leave at room temperature for 0.5 to 2 hours.

The following examples illustrate the invention (S in the examples are by weight).

He did

100 g of thiodipropionic acid dihydrazide _(A) and 275 g of methyl 3- (3-methyl-5-tBu-4-hydroxyphenyl) propionate (B) was heated with stirring in a melt at 150 ° C under a nitrogen atmosphere for 3 hours. The resulting product, N ' -bis / 3- (3-methyl-5-tBu-4-hydroxyphenyl) propionate / -thiodipropionodihydrazid _(Ia) was crystallized from a mixture toluene - hexane 1: 1st It had a melting point of 165-167 ° C, characteristic absorption bands in the XR region: phenolic OH 3,620 cm -1, thio 2,850 cm -1 hydrazido 1,645 cm

Example 2

100 g of thiodipentanoic acid dihydrazide (A _b ) was dissolved in anhydrous morpholine together with 50 ml of pyridine. 280 g of 3- (3-octadeoyl-5-t-Bu-4-hydroxyphenyl) propionic acid chloride (C) also soluble in anhydrous morpholine were added to the solution. After stirring for 60 minutes, water was added to the morpholine solution and the precipitated product was aspirated on a frit.

After crystallization from hexane, the resulting N ', N'-bis [3- (3-octadeoyl-5-t-Bu-4-hydroxyphenyl) propiono] -thiodipentanodihydrazide (I.) was characterized by a melting point of 109-111 ° C and had the characteristic ^D - 1 -1 -1 IR absorption bands: phenolic OH 3,640 cm, thio 2,850 cm, hydrazido 1,645 cm

Example 3

N ', N'-bis / 3- (3,5-child-Bu-4-hydroxyphenyl) propiono] -thio dipropionodihydrazide (I _c ) was prepared as described in Example 1, substituting methyl acid ester for (B _a ) 3- (3,5-ditBu-4-hydroxyphenyl) propionic acid in the same molar amount. The product (I _c ) was added at a concentration of 0.1 and 0.2% to powdered, unstabilized polypropylene having a flow index of 4.

The film prepared from the blend had induction period values of IP 130 ° C shown in Table X.

He attaches

Following the procedure of Example 2, N ', N'-bis / 3- (3,5-ditBu-4-hydroxyphenyl) propionol / thiodioctadecanodihydrazide (1 ^) was prepared using 3- (3) dihydrazide instead of (A ^). 5-ditBu-4-hydroxyphenyl) propionic acid. the stabilizing efficiency (1) was monitored in the same manner as in Example 3 and the values are shown in Table I.

Example5

In the same manner as in Example 3, the stability of polypropylene stabilized with 0.1 and 0.2% IRGANOX 1 076 1 076 (3- (3,5-ditBu-4-hydroxyphenyl) propionic acid octadecyl ester and 0.1 and 0.2%) was observed. DSTDP (dioctadecylthlodipropionate) The results are shown in Table I.

Example 6

Compound _<Ia) prepared in Example 1 in the same manner as in Example 3 A mixture with commercial stabilizers are evaluated for stabilizing efficacy. The results are shown in Table X.

Claims (3)

Table Example Compound. % IRGANOX 1,076% DSTDP% Induction Period / Days / IP 130 ° C 0.1 170 1Xa 0.2 210 0.1 132 2 * b 0.2 185 0.1 160 3Tc 0.2 208 0.1 170 4Td 0.2 201 0.1 105 5 0.2 150 - 0.1 64 0.2 90 0.1 0.1 0.1 135 6Ta 0.2 0.2 0.2 161 SCOPE OF THE INVENTION 1. N ', N * -bis [3- (3,5-dialkyl-4-hydroxyphenyl) propiono] -thiodialkanodihydrazides of the general formula (I): O O .R, Β B '(CH ₂ ) _n -C-NH-NH-C- (CH ₂ ) ₂ —OH / - ^R 2' ^R 1 (CH ₂ ) _{n -} C — NH-NH-C- (CH ₂₎ I ₂ —OH (I) wherein ^R 1 ' ^R 2 n = alkyl of 1 to 24 carbon atoms = 1 to 24 2. A process for the preparation of compounds of formula (I) according to claim 1, characterized in that the thiodialanoic acid dihydrazide of formula (A) is reacted. D JCH) - - ^C - ¹⁴¹¹ - ^NH 2 (A) '(CH 2) - C - NH - NH ² ft ² where n is as defined in point 1 B with 3- (3,5-dialkyl-4-hydroxyphenyl) propionic acid alkyl ester of formula (B) HO— (ť R ₂ (ch ₂ ) ₂ "C-or ₃ (B) where, R, R are as defined in paragraph 1 ^R 3 = alkyl having 1 to 12 carbon atoms at temperatures of 20 to 300 ° C for 0.1 to 10 hours. A process for the preparation of compounds of formula (I) according to claim 1, characterized in that the thiodialanoic acid dihydrazide of formula (A) is reacted with a 3- (3,5-dialkyl-4-hydroxyphenyl) propionic acid halide of formula (C) with HIM O> - (CH ₂ ) ₂ -CX (C) wherein Rp R ₂ are as defined in Item 1 X is halogen at temperatures of 0 to 200 ° C for 0.1 to 10 hours Compound (A) is either in a 2-fold molar excess relative to (C) or half of it is replaced with trialkylamines or pyridine.