FR2508911A1 - PROCESS FOR THE PREPARATION OF PENTAERYTHRITOL MONOACETAL ESTERS AND NOVEL PRODUCTS THUS OBTAINED, USEFUL AS ADDITIVES FOR POLYMERS - Google Patents

Abstract

THE INVENTION RELATES TO MONOACETAL ESTERS OF PENTAERYTHRITOL. MONOACETALS RESULT FROM THE REACTION OF A 4-HYDROXYPHENYLPROPIONALDEHYDE AND PENTAERYTHRITOL, THE REACTION OF THIS MONOACETAL WITH A CHLORIDE OF FORMULA CL-AX OR A IS PO AND X IS AN ORGANIC RADIAL, PREFERABLY AROMATIC ESTERS PROVIDES THEM . THESE ESTERS ARE USEFUL, IN LOW PROPORTIONS, FOR STABILIZING POLYMER COMPOSITIONS, ESPECIALLY OLEFINE POLYMERS.

Description

1.

  The present invention relates to certain es-

  ter 3 of pentaerythritol monoacitals More particular-

  ment, it relates to the esters which contain a group

  pe ph 6 nolic in their structure It also relates to

  ment to a process by which these esters can be prepared. The esters of the present invention are useful as polymer additives They are especially useful in olefin polymer compositions, for example

  polypropylene compositions, where they are used to confer

  rer thermal stability to such compositions They are also useful as intermediates in the preparation of phenolic ethers which in turn are useful as plasticizers in polyester resins Generally, 1 olefin polymer compositions have physical and chemical properties which can deteriorate during the

  manufacturing, storage, processing and use

  In order to overcome this degradation, or at least to inhibit it, additive systems have been developed which serve to stabilize these polymers with regard to degradation.

  physical and chemical effects caused by exposure to

  ordinary environmental editions however all of these additive systems while they are effective in their

  object, have one or more disadvantages.

2.

  The olefin polymers are specially sensitive

  due to degradation by oxidation The temperatures

  high requirements for common processes

  processing such as rolling on rolls, molding

  injection molding, extrusion and the like, promote in-

  variably oxidation because these operations are ef-

  carried out under ordinary atmospheric conditions,

  that is, there is exposure to oxygen from the atmosphere-

sphere.

  The importance of oxidation of resinous polymers

  of in the harmful effect it has on rheology, mor-

  phology, color, clarity, luster and other pro-

  physical properties Impact resistance can be

  due; the surface may become cracked or cracked Even a darkening of the color can result in a sufficient aesthetic disadvantage for the composition

  of olefin polymer is no longer usable in its

fold expected.

  U.S. Patent No. 3,948,945 presents

  hydroxybenzaldehyde acetals Acetals are the pro-

  reaction products of 2,2-dimethyl-1,3-propanediol, pentaerythritol, ethylene glycol, 1,2-ethanediol, toluene-3,4-dithiol, etc. Thus, the alcoholic precursor

  is polyhydroxylated However, the reaction of penta 6 rhyth-

  tol is carried out until completion, i.e. all aliphatic hydroxy groups are acetalized Acetals are said to be effective stabilizers for

organic materials.

  U.S. Patent 4,013,619 presents

  acetals of certain hydroxyphenylacetaldehydes and hydroxy-

  phenylpropionaldehydes, in some cases (see columns 16 and 17), with rests of penta 6 rythritol Acetals

  are monoacetals or diacetals, but monoacetals-

  tals do not contain unreacted aliphatic hydroxy groups Acetals are said to be effective as thermal stabilizers in

synthetic resins.

3 2508911

  U.S. Patent No. 4,151,211 discloses 4-hydroxyphenylpropionaldehyde acetals and compounds

  hydroxy or mercapto such as pentaerythritol, do-

  decylmercaptan and various other reactants

  as well as their use for stabilizing polypropylene However, none of the acetals

  contains unreacted aliphatic hydroxy groups.

  French Patent No. 2,301,558 presents certain

  pentaerythritol and 3,5-di-t-butyl-4-hydro- diacetals

  xyphenylpropionaldehyde and 3,5-di-t-butylbenzaldehyde.

  The invention of the present application relates to a

  ester of a pentaerythritol monoacetal having the structure

  re:> XH / t (CH 2 Y-C / e C (C, 20) 2 (A-X)

R 'R 2 2 2 22

  véRl \ 2 OCH 2 R 1 R o R is an alkyl, cycloalkyl or aralkyl group having * 1 3-10 carbon atoms, R 1 is an alkyl group having 1-6 carbon atoms, R is a lower alkyl group or l 'hydrogen, A is O or PO, X is an organic radical,

VS

VS

n is 0-3 and p is 1-2.

  The present invention also includes the process

  die for preparing these esters consisting in reacting a pentadrythritol monoacetal having the structure: - \ s OCH 2 HO \ / (CH 2) -CH C (CH 2 o H) 2

'OCH 2

  o R is an alkyl, cycloalkyl or aralkyl group having 3-10 carbon atoms, R is an alkyl group having-1-6 carbon atoms and R is a lower alkyl group or hydrogen, with an ester-forming compound having the structure Clm-AX om is 1 or 2, A is O or PO, X is C an organic radical and N is 0-3 The expression "lower alkyl" denotes an alkyl group having 1-4 carbon atoms.

  Illustrative species of R include-

  the methyl, ethyl, isopropyl, t-butyl, t-amyl, 2,2 'dimethylbutyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl, benzyl and phenylethyl groups; some change

  by way of illustration of R 1 include methyl groups

  , ethyl, isopropyl, t-butyl, t-amyl and 2,2 '-dimethyl-

  butyl; Illustrative species of R including

  The methyl, ethyl, n-propyl, isobutyl and hydrogen groups are preferably at least one of the R and R is a bulky group, for example the t-butyl group or

cyclohexyl.

  The organic radical X is an aromatic radical, that is to say that it contains a benzene nucleus It can be a substituted aryl group, that is to say an alkylphenyl group (where the alkyl group has 1-6 carbon atoms), such as the group 4-t-butylphenyl, 2,4-di-t-butylphenyl or 2,6diisopropylphenyl; or a hydroxyphenyl group such as the 4hydroxy-2-methyl-3-t-butylphenyl group,

  4-hydroxy-2,3-di-t-butylphenyl, 4-hydroxy-3,5-di-t-butyl-

  phenyl or 4-hydroxy-2-t-butyl-5-n-octylphenyl The radi-

  aromatic cal can be a radical which is attached direct-

  ment to group A, i.e. through a

  benzene carbon atom, or it can be fixed by the in-

  intermediate of an aliphatic carbon atom, for example

  benzyl, 2-phenylethyl, 2- (4-hydroxyphenyl) ethyl-

  le and 2- (4-hydroxy-3,5-di-t-butylphenyl) ethyl.

  In general, X is a phenyl group, an alkylphenyl group or a (hydroxyphenyl) alkyl group, o le or 4.

  the alkyl groups in each case have 1-6 carbon atoms

  bone. The process of the present invention involves the reaction of the pentaerythritol acetal indicated above with the acid chloride under conditions such that the evolution of gaseous hydrochloric acid is brought about.

  reaction is slightly exothermic and it is therefore

  desirable to use external cooling

  to control the reaction Stoichiometric quantities

  that reagents should be used for the best results, i.e. two

  moles of carboxylic acid chloride per mole of monoace-

  tal of pentaerythritol, or one mole of dichlorophosphite

  per mole of pentaerythritol monoacetal are used.

  A gaseous hydrochloric acid acceptor is

  employed, usually a tertiary aliphatic amine such as

  that triethylamine or tri-n-butylanine, i.e.

  re an amine having 3-12 carbon atoms and the reaction

  is best performed in a solvent Typical solvents

  2 that include the toluene dioxane, benzene and aina-

  logue Any inert solvent is suitable. The reaction temperature is usually between about C and about 1000 C.

  The reagents, the solvent and the accept

  hydrochloric acid gas are mixed, stirred

  until the reaction is complete and the product solids

  of desired is separated If a pure product is desired the re-

  crystallization from a hot aliphatic hydrocarbon (such

  than hexane) will generally be used for this purpose.

  The process is illustrated by the following examples.

EXAMPLE 1

  A mixture of 13.0 g (0.034 mole) of the pentaerythritol monoacetal and 3- (4-hydroxy-3,5-di-t-butylphenyl)

  propionaldehyde, 17.6 g (0.066 mole) 4- chloride

  hydroxy-3,5-di-t-butylhenzoyl and 115 ml of toluene is stirred in an ice bath until the temperature is approximately 3 ° C., and above this is added 11.5 ml 5. (8, 38 g 0.083 mol) of triethylamine There follows an exothermic reaction and the temperature rises to C. Stirring is continued for 45 minutes, then the mixture is heated to 80 ° C. and filtered The filtrate is removed to provide a residue weighing 33.0 g; it is crystallized from hot hexane to give 11.75 g

  (42.5% of theory) of white crystals at p f of 123-

127 C.

EXAMPLE 2

  A 9.59 g (0.025 mole) klange of monoacetal

  pentaerythritol and 3- (4 '-hydroxy-3', 5 '-di-t-butyl-

  phenyl) propionaldehyde, 10.4 ml (7.6 g 0.107 mole) of triethylamine and 90 ml of dioxane is prepared and stirred until all of the products are in solution;

  a solution of 15 g (0.051 mole) of chloride 3- (4 '-

  hydroxy-3 ', 5' -di-t-butylphenyl) propionyl is added len-

  with external cooling, and stirring is continued for 90 minutes at room temperature

  after all of the products have been added The time-

  mixing temperature is high up to 80 "C and maintained

  at this value for 90 minutes, then the mixture is

  very The filtrate is evaporated to dryness and the residue is crystallized

  metallized in hot hexane to provide 16.15 g (71%

  theory) of the desired diester p f 95-100 C.

EXAMPLE 3

  In a stirred mixture of 9.5 g (0.025 mole) of

  monoacetal of pentaerythritol and 3- (4 '-hydroxy-3', 5 '-di-

  t-butylphenyl) propionaldehyde, 10 ml (7.3 g 0.103 mo-

  le) of triethylamine and 100 ml of toluene, is added,

  with stirring, 7.68 g (0.025 mole) of dichlo- phosphite

  ro-2,4-di-t-butylphenyl An exothermic reaction ensues

  mique and the reaction temperature is maintained at

  below 40 C by means of an ice bath When the re-

  action has subsided, the product mixture is filtered and

  the filtrate is evaporated to give 15.0 g of a residue gom-

  meux jaune Recrystallization from hot heptane supplied

  nit 12.5 g (81% of theory) of a light yellow solid, at

mp 138-140 'C.

6.

EXAMPLE 4

  The procedure of Example 2 is repeated

  except that the reactant formed from monoacetal pro-

  comes from 3- (2 ', 3' -dimethyl-4-hydroxy-5-t-butylphenyl) pro-

pionaldehyde.

EXAMPLE 5

  The procedure of Example 3 is repeated except

  that the reactant formed from phosphite is phos-

  dichloro-2,6-di-t-butylphenyl phite.

  The acetal esters of the present invention

  are, as indicated above, useful in composites

  olefin polymer they are usually present

  in such compositions in combination with a thiodi-

  dialkyl propionate or the alkyl group is a group

  having 10-20 carbon atoms; dis dithiopropionate

  tearyl is preferred The acetal ester is used at

  centrations ranging from approximately 0.01% to approximately 1.0%; the

  dialkyl thiodipropionate is used in concentrates

  trations ranging from about 0.05% to about 0.75%.

  The effectiveness of the acetal esters of the invention as polymer stabilizers is indicated by the results summarized in the table below. The results come from thermal stability tests carried out at 1500 C. Each sample is heated to this temperature and inspected at periodic intervals until it fails (as evidenced by embrittlement,

  cracking and / or cracking) The samples are

  each of polypropylene containing 0.10 pph (parts per 100 parts of resin), calcium stearate and other additives which are indicated The color ratings (Hunter Lb) are assigned to each sample before (initial assessment) and after (final evaluation) 600 hours at 150 * C, The evaluation of stability is measured in the form of the number of hours required for failure, and is given

  born by the average of these samples.

  7. Color 4 Ester DSTDP Evaluation Evaluation Stability of acetal (pph) initial final (pph) _ Product of

example 1

0.03 0.25 75.8 74.0

0.05 0.20 1264

0.05 0.30 1,368

0.075 0.25 75.6 73.9 1,632

0.075 0.30 __ 1800

Product of

example 2

0.03 0.25 75.6 74.0 1304

0.05 0.20 1464

0.05 0.30 1,664

0.75 0.25 74.8 72.1 1,632

0.75 0.35 ____ 1824

Product of

example 3

0.05 0.25 74.3

0.10 0.25 74.5 67.9

Product of

example 4

0.05 0.25 1,416

Product of

example 5

0.05 0.25 76.1

0.10 0.25 74.3 70.8

No pro-

  duit dui 5 0, Z 5 168 All the parts and all the percentages All the parts and all the previous percentages are expressed, unless otherwise indicated, by weight The present invention is not limited to the embodiments which come from be described she

  is on the contrary subject to modifications and

  laughing who will appear to those skilled in the art.

O 8.

Claims (8)

  1 Process for the preparation of mo-   pentaerythritol noacetal, characterized in that it   is to react a pentaerythritol monoacetal having the formula HO z IOCH 2. (CH 2) CH C (CH 20) 2   OCH 2 R 2 o R is an alkyl, cycloalkyl or aralkyl group having 3-10 carbon atoms, R 1 is an alkyl group having 1-6 carbon atoms, and R 2 is a lower alkyl group or hydrogen, with an ester-forming compound having the structure C 12-AX where A is PO, X is an organic radical and N is 0-3.   2 Method according to claim 1, character-   laughed in that R and R 1 each represents a t-butyl group and R 2 is hydrogen.   3 Method according to claim 1, characterized in that R is the t-butyl group and R 1 and R 2 represent each methyl group.   4 Method according to claim 1, characterized   in that X is an aromatic group.   Method according to claim 4, characterized   in that X is a phenyl group.   6 Method according to claim 4, characterized   in that X is an alkylphenyl group.   7 As a new industrial product, ester of a pentaerythritol monoacetal having the structure: 9. R OCHO HO (-CHCCH 2 0) 2 (A-X) OCH 2 R 1 R 2   o R is an alkyl, cycloalkyl or aralkyl group having 3-10 carbon atoms, R 1 is an alkyl group having 1-6 R 2 carbon atoms, R 2 is a lower alkyl group or hydrogen, A is PO, X is an organic radical and n is 0-3.   8 Ester according to claim 7, characterized   in that X is an aromatic group.   9 Ester according to claim 8, characterized   in that X is a phenolic group.   Ester according to claim 8, characterized   in that X is an alkylph 6 nyl group. 10.