WO2000068192A2

WO2000068192A2 - Process for the preparation of (di)alkylperoxy esters of (di)carboxylic acids

Info

Publication number: WO2000068192A2
Application number: PCT/EP2000/004393
Authority: WO
Inventors: Manfred Bergfeld; Axel Carstens
Original assignee: Akzo Nobel NV
Current assignee: Akzo Nobel NV
Priority date: 1999-05-05
Filing date: 2000-05-02
Publication date: 2000-11-16
Anticipated expiration: 2001-11-05
Also published as: KR20020003875A; WO2000068192A3; JP2002544189A

Abstract

The invention relates to a process to make (di)alkylperoxy esters of (di)carboxylic acids by reacting a (di)carboxylic acid (di)vinyl ester with an alkylhydroperoxide. Preferably, a base catalyst is used, while the use of a phase transfer catalyst is optional. Optionally one or more solvents are used. Preferably the acetaldehyde that is formed is removed from the perester by distillation and used in further chemical processes.

Description

Process for the preparation of (di)alkylperoxy esters of (di)carboxylic acids

The present invention pertains to a process for the preparation of alkylperoxy esters of carboxylic acids and di(alkylperoxy esters) of dicarboxylic acids.

For the preparation of alkylperoxyesters of carboxylic acids Ullmann's Encyclopedia of Industrial Chemistry 5th. Ed. (1991), Vol. A 19, p. 215, Chapter 6.2 describes the reaction of hydroperoxides with carboxylic acids, carboxylic acid halides, carboxylic anhydrides, or N-acylimidazoles.

The most important reaction for the preparation of alkylperoxy esters of carboxylic acids, and the one most frequently used in industry, is the reaction of alkylhydroperoxides with acid halides in the presence of a base according to equation (1).

O O

R¹— C-Hal + H-O-O-R³ + Base → R¹— C-O-O-R³ + H-Base⁺Har (1)

However, acid halides are highly corrosive, so that high demands are made on the corrosion resisting quality of all plant parts which come into contact with the acid halides, which makes the process more expensive. Moreover, the acid halides are comparatively expensive themselves and have a tendency to form halogenated side products. Finally, according to equation (1) it is not only the desired alkylperoxy(di)carboxylic ester which is obtained but also, at the same time and in equimolar amount, undesired salt is formed, a waste product. For instance, when acid chlorides are used with pyridine as base, 1 mole of pyridinium hydrochloride is formed per mole of alkylperoxycarboxylic acid ester or, when NaOH is used as base, 1 mole of NaCI is formed per mole of alkylperoxycarboxylic acid ester, which waste product has to be disposed off. Disposing of halogenated products, including common salt, is costly and undesired from an environmental point of view.

Hence there is need for a process for the preparation of peroxyesters which avoids the aforementioned drawbacks.

For this reason the present invention has for its object to provide a process for the preparation of peroxyesters which uses non-corrosive raw materials, does not yield halogenated side products, and despite the use of a base does not lead to the formation of salt waste.

Surprisingly, this objective is met by the process according to the invention, wherein a carboxylic acid vinyl ester or a dicarboxylic acid divinyl ester is reacted with an alkylhydroperoxide using a base and, optionally, a phase transfer catalyst.

A preferred embodiment of the invention pertains to a process to make (di)alkylperoxy (di)carboxylic acid esters of formulae (I) and (II),

O O

₃ II _? II ₃ R— O-O-C-R-C-O-O-R³ _(N) by reacting a (di)carboxylic acid vinyl (di)ester of formula (III) or (IV)

with an alkylhydroperoxide of formula (V) [H-O-O]_n-R³ (V) wherein R¹, R², and R³ represent hydrocarbon groups that are optionally substituted with a hydroxyl group, and wherein R¹ optionally contains an ester moiety, and n stands for 1 , 2 or 3.

Surprisingly, the process according to the invention avoids not only the formation of halogen-containing waste, but as is clear from equation (2), describing the reaction of a compound of formula (III) with a compound of formula (V) to make a product of formula (I) wherein n = 1 , it also produces a valuable side-product in the form of acetaldehyde in an equimolar amount, which can be put to multiple use, e.g., for the preparation of acetic acid, acetic anhydride, ethyl acetate, peracetic acid, crotonaldehyde, chloral, glyoxal, and pentaerythritol.

O Base O

R¹— C-0-CH=CH₂ + H-O-O-R³ → R¹— C-O-O-R³ + CH₃C(O)H (2)

The reaction according to the invention of a dicarboxylic acid divinyl ester of formula (IV) with an alkylhydroperoxide of formula (V) (n = 1) according to equation (3) even leads to the formation of 2 moles of acetaldehyde per mole of alkylperoxydicarboxylic acid ester of formula (II), without the formation of salt waste.

O O Base

CH^CH-0-C-R-C-0-CH=CH₂ + H-O-O-R³

O O

₃ II , II ₃

R— O-O-C-R-C-O-O-R³ + 2 CH₃C(O)H (3)

In a preferred embodiment, the process according to the invention relates to the manufacture of compounds wherein R¹ is selected from the group consisting of methyl, ethyl, propyl (any isomer), butyl (any isomer), pentyl (any isomer), hexyl (any isomer), heptyl (any isomer), octyl (any isomer), nonyl (any isomer), decyl (any isomer), undecyl (any isomer), dodecyl (any isomer), 2-ethylhexyl, cyclohexyl, phenyl, methyl substituted phenyl (any isomer), benzyl, C₆H₅OCH₂-, propenyl, C₆H₅CH=CH-, and mono-methyl, -ethyl, -propyl, or -butylesters (any isomer) of formula C_mH_2m+ι-O-C(O)-R²-, wherein m=1-4 and R² has the meaning as presented in the next paragraph.

In another preferred embodiment, the process according to the invention relates to the process to make compounds wherein R² is a linear or branched alkylene group with 1 to 10 C-atoms; specifically -(CH₂)_n-, wherein n = 1 to 10, -CH₂CH(CH₃)CH₂C(CH₃)₂-, -CH(CH₃)CHC(CH₃)₂-, and -CH₂CH(CH₃)-; cyclohexyl (any isomer); -CH₂-C₆H₁₀-CH₂- (any isomer); or phenyl (ortho or para). Also mixtures of divinyl esters of diacids, with the indicated meaning for R², may be used.

Another preferred embodiment of the invention is directed to processes to make compounds wherein R³ is chosen such that R³OOH is one of the following alkyl (di)hydroperoxides. Tert-butyl hydroperoxide, tert-amylhydroperoxide, tert- hexylhydroperoxide (all isomers), tert-heptylhydroperoxide (all isomers), 2,4,4- trimethylpentyl-2-hydroperoxide, α-cumylhydroperoxide, hydrogenated α- cumylhydroperoxide (C₆HnC(CH₃)₂OOH), 1 ,1-dimethyl-3-hydroxybutyl-1- hydroperoxide, p-menthylhydroperoxide, 2,5-dimethyl-2,5dihydroperoxy hexane, 2,5-dimethyl-2,5dihydroperoxy hexyne, and (meta and/or para) di(hydroperoxyisopropyl)benzene. Also, R³ can be chosen such that R³OOH is a hydroperoxide obtainable by the reaction of ketones with H₂O₂, as described in Organic Peroxides, Vol. 2, Chapter 1 „ Hydroperoxides," pp. 1-152 (1971), published by D. Swern, ISBN 0471839612. Furthermore, a mixture of any of the above mentioned hydroperoxides can be used according to this embodiment.

Alkylperoxycarboxylic acid esters of formula (I) that are preferably prepared in accordance with the process of the invention include: α-cumylperoxyneodecanoate, hydrogenated α-cumylperoxyneodecanoate, 2,4,4-trimethylpentyl-2-peroxyneodecanoate, tert-amylperoxyneodecanoate, tert-butylperoxyneodecanoate, 1 ,1-dimethyl-3-hydroxybutyl-1-peroxy- neodecanoate, α-cumyiperoxypivalate, hydrogenated α-cumylperoxypivalate, 2,4,4- trimethylpentyl-2-peroxypivalate, tert-amylperoxypivalate, tert-butylperoxy- pivalate, 1 ,1-dimethyl-3-hydroxybutyl-1-peroxypivalate, α-cumylperoxy-2-ethylhexanoate, hydrogenated α-cumylperoxy-2-ethyl- hexanoate, 2,4,4-trimethylpentyl-2-peroxy-2-ethylhexanoate, tert-amylperoxy-2- ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, 1 ,1-dimethyl-3-hydroxybutyl- 1 -peroxy-2-ethylhexanoate, α-cumylperoxydiethylacetate, hydrogenated α-cumylperoxydiethylacetate, 2,4,4-trimethylpentyl-2-peroxydiethylacetate, tert-amylperoxydiethylacetate, tert- butylperoxydiethylacetate, 1 ,1-dimethyl-3-hydroxybutyl-1-peroxydiethylacetate, α-cumylperoxyisobutanoate, hydrogenated α-cumylperoxyisobutanoate, 2,4,4- trimethylpentyl-2-peroxyisobutanoate, tert-amylperoxyisobutanoate, tert- butylperoxyisobutanoate, 1 ,1-dimethyl-3-hydroxybutyl-1-peroxyisobutanoate, α-cumylperoxy-3,5,5-trimethylhexanoate, hydrogenated α-cumylperoxy-3,5,5- trimethylhexanoate, 2,4,4-trimethylpentyl-2-peroxy-3,5,5-trimethylhexanoate, tert-amylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxy-3,5,5-trimethyl- hexanoate, 1 ,1-dimethyl-3-hydroxybutyl-1-peroxy-3,5,5-trimethylhexanoate, α-cumylperoxyacetate, hydrogenated α-cumylperoxyacetate, 2,4,4-trimethyl- pentyl-2-peroxyacetate, tert-amylperoxyacetate, tert-butylperoxyacetate, 1 ,1- dimethyl-3-hydroxybutyl-1-peroxyacetate, α-cumylperoxybenzoate, hydrogenated α-cumylperoxybenzoate, 2,4,4- trimethylpentyl-2-peroxybenzoate, tert-amylperoxybenzoate, tert- butylperoxybenzoate, and 1 ,1-dimethyl-3-hydroxybutyl-1-peroxybenzoate.

Alkylperoxydicarboxylic acid esters of formula (II) preferably prepared with the process according to the invention are: di-tert-butylperoxy malonate, di-tert-butylperoxy succinate, di-tert-butylperoxy glutarate, di-tert-butylperoxy adipate, di-tert-butylperoxy azelate, di-tert- butylperoxy phthalate, di-tert-amylperoxy malonate, di-tert-amylperoxy succinate, di-tert-amylperoxy glutarate, di-tert-amylperoxy adipate, di-tert-amylperoxy azelate, di-tert- amylperoxy phthalate, di(1 , 1 -dimethyl-3-hydroxybutyl-1 -peroxy) malonate, di(1 , 1 -dimethyl-3- hydroxybutyl-1-peroxy) succinate, di(1 ,1-dimethyl-3-hydroxybutyl-1 -peroxy) glutarate, di(1 ,1-dimethyl-3-hydroxybutyl-1 -peroxy) adipate, di(1 ,1-dimethyl-3- hydroxybutyl-1 -peroxy) azelate, di(1 ,1-dimethyl-3-hydroxybutyl-1-peroxy) phthalate,

2,5-dimethyl-2,5-bis(acetylperoxy)hexane, 2,5-dimethyl-2,5-bis(2-ethylhexanoyl- peroxy)hexane, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 2,5-dimethyl-2,5-bis(acetylperoxy)hexyne, 2,5-dimethyl-2,5-bis(2-ethylhexanoyl- peroxy)hexyne, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexyne, (meta and/or para) di(neodecanoylperoxyisopropyl) benzene, (1 ,3 or 1 ,4)-di(neodecanoylperoxyisopropyl)cyclohexane, -di(α-cumylperoxy- carbo)cyclohexane, -di(hydrogenated α-cumylperoxycarbo)cyclohexane, -di(2,4,4-trimethylpentyl-2-peroxycarbo)cyclohexane, -di(tert-butylperoxycarbo)- cyclohexane, -di(tert-amylperoxycarbo)cyclohexane, and -di(1 ,1-dimethyl-3- hydroxybutyl-1-peroxycarbo)cyclohexane.

In the process according to the invention the use of a solvent may be advantageous. Such solvents include water, an organic solvent, and mixtures of such solvents. As an organic solvent, conventional phlegmatizers can be used, such as isododecane, di-tert-butyl phthalate and the like. The use of these conventional phlegmatizers is preferred if the acetaldehyde that is formed can be easily separated from the resulting perester. However, in order to facilitate the removal of the acetaldehyde, e.g. through stripping, flash distillation, or other conventional means, it can be preferred to use an (aliphatic) organic solvent with 5 to 8 C-atoms. In that case n-pentane or n-hexane are especially preferred. However, if the use of such a low-boiling solvent is desired, it may be preferred to use it in combination with a conventional phlegmatizer in order to prevent hazardous situations to occur. The solvent (or part of the solvent) may be present in the reactor before it is charged with one or more of the reactants. However, (part of) the solvent may also be added together with one or both of the reactants.

The base suitable for use as a catalyst in the process of the invention preferably is an alkaline (earth) hydroxide or an alkaline (earth) oxide, with the use of calcium hydroxide or sodium hydroxide as alkaline (earth) hydroxide and of calcium oxide or sodium oxide as alkaline (earth) oxide being especially preferred. Such base is used in a conventional way and can be added to the reactor (wholly or partially) prior to, or together with, the other reactants.

Any commonly used phase transfer catalyst, including compounds like tetra- butyl ammonium chloride, tetra-butyl ammonium bromide, tetra-butyl ammonium hydrosulfate, benzyl tri-ethyl ammonium chloride, benzyl tri-methyl ammonium chloride, dimethyl amino pyridine, and methyl tri-capryl ammonium chloride, can be employed as the phase transfer catalyst optionally used in the process according to the invention. The use of methyl tri-capryl ammonium chloride, which is known by the trade designation Aliquat 336, being preferred.

The molar ratio of the vinyl groups in the (di)carboxylic acid (di)vinyl ester to the hydroperoxide groups in the alkylhydroperoxide in the process according to the invention preferably is in the range of 0.7 : 1.0 to 1.2 : 1.0. A ratio of 0.8 : 1.0 to 1.0 : 1.0 (mole/mole) is preferred to minimise the contamination of the resulting perester with the starting vinyl ester.

From unoptimized tests it was concluded that a process is preferred wherein the molar ratio of vinyl groups (from the (di)carboxylic acid (di)vinyl ester) to the base catalyst is in the range of 3 : 1 to 25 : 1 (mole/mole). The reaction according to the invention preferably is carried out at a temperature in the range of -10 to + 60°C. However, for safety reasons, a lower maximum temperature may have to be used. Therefore a temperature in the range of 0 to + 20°C may be preferred.

The process according to the invention preferably is carried out at standard pressure. However, a further preferred embodiment of the invention relates to a process being worked at a pressure below atmospheric, in which the formed acetaldehyde is removed from the reaction solution by distillation. Because such a process requires lower distillation temperatures, it is less hazardous. If desired, a carrier gas can be used to facilitate the removal of the acetaldehyde. Preferably, the acetaldehyde that is formed is removed from the perester and used in further chemical processes.

The (di)alkylperoxy(di)carboxylic acid esters prepared according to the invention can be used as polymerisation initiators, as hardeners for resins, for the modification of polymers, e.g., for cross-linking polyethylene, for the decomposition of polymers, for improving the cetane number in fuels, and as synergist in fireproofing agents. In addition, the alkylperoxycarboxylic acid esters can be used in preparatory organic syntheses such as for the epoxidation of olefins.

The following examples serve to further elucidate the invention. Example 1

Into a 100 Erlenmeyer flask with internal magnetic stirrer and dropping funnel were charged 7.5 g of a 70% solution of tert-butylhydroperoxide in water (50.1 mmoles tert-butylhydroperoxide), 10 ml of n-hexane, 0.3 g of NaOH (7.5 mmoles), and 0.3 g of Aliquat 336. To this were added dropwise at 20°C within 30 minutes 7.41 g of vinylbenzoate (52.9 mmoles). Next, there was 20 hours of after-stirring at 20°C. This resulted in an aqueous phase and an organic phase containing the tert-butylperoxybenzoate. Gas chromatographic analysis showed a conversion to tert-butylperoxybenzoate, calculated on vinylbenzoate, of 88.9%. The acetaldehyde that was formed can be used in other processes, optionally after further purification.

Example 2

Into a 100 Erlenmeyer flask with internal magnetic stirrer and dropping funnel were charged 6.5 g of a 70% solution of tert-butylhydroperoxide in water (50.5 mmoles of tert-butylhydroperoxide), 10 ml of n-pentane, and 0.5 g of NaOH (12.5 mmoles). To this were added dropwise at 20°C within 30 minutes 8.3 g of vinyl-2-ethylhexanoate (48.8 mmoles). Next, there was 20 hours of after-stirring at 20°C. This resulted in an aqueous phase and an organic phase containing the tert-butylperoxy-2-ethylhexanoate. Gas chromatographic analysis showed a conversion to tert-butylperoxy-2-ethylhexanoate, calculated on vinyl-2- ethylhexanoate, of 86.4%. The acetaldehyde that was formed can be used in other processes, optionally after further purification.

Example 3

Into a 100 Erlenmeyer flask with internal magnetic stirrer and dropping funnel were charged 6.3 g of vinylpivalate (49.2 mmoles), 10 ml of n-pentane, and 0.1 g of Aliquat 336. To this was added dropwise at 20°C within 30 minutes a solution composed of 0.1 g of NaOH (2.5 mmoles) and 6.5 g of a 70% solution of tert-butylhydroperoxide in water (50.5 mmoles of tert-butylhydroperoxide). Next, there was 20 hours of after-stirring at 20°C. This resulted in an aqueous phase and an organic phase containing the tert-butylperoxypivalate. Gas chromatographic analysis showed a conversion to tert-butylperoxypivalate, calculated on vinylpivalate, of 60.2%. The acetaldehyde that was formed can be used in other processes, optionally after further purification.

Claims

1. A process for the preparation of (di)alkylperoxy esters of (di)carboxylic acids, characterised in that a substituted or unsubstituted (di)carboxylic acid (di)vinyl ester is reacted with a substituted or unsubstituted hydrocarbylhydroperoxide.

2. A process according to claim 1 wherein said reaction takes place in the presence of a base catalyst and an optional phase transfer catalyst.

3. A process according to claim 1 or 2, characterised in that the (di)alkylperoxy esters of (di)carboxylic acids are selected from the group of compounds in accordance with formulae (I) and (II)

O O

₃ II , II ₃ R — O-O-C-R-C-O-O-R³ _(||) wherein R¹, R², and R³ represent hydrocarbon groups that are optionally substituted with a hydroxyl group and that optionally contain an ester moiety, and wherein n stands for 1 , 2 or 3.

4. A process according to any one of claims 1-3, characterised in that R¹ is selected from the group consisting of methyl, ethyl, propyl (any isomer), butyl (any isomer), pentyl (any isomer), hexyl (any isomer), heptyl (any isomer), octyl (any isomer), nonyl (any isomer), decyl (any isomer), undecyl (any isomer), dodecyl (any isomer), 2-ethylhexyl, cyclohexyl, phenyl, methyl substituted phenyl (any isomer), benzyl, C₆H₅OCH₂-, propenyl,

C₆H₅CH=CH-, and mono-methyl, -ethyl, -propyl, or -butylesters (any isomer) of formula CmH_2m+ι-O-C(O)-R²-, wherein m=1-4 and R² has the meaning as given in claim 5.

5. A process according to any one of claims 1-4, characterised in that R² is selected from the group consisting of linear or branched alkylene groups with 1 to 10 carbon atoms; specifically -(CH₂)_n-, wherein n = 1 to 10, -CH₂CH(CH₃)CH₂C(CH₃)₂-, -CH(CH₃)CHC(CH₃)₂-, and -CH₂CH(CH₃)-; cyclohexyl (any isomer); -CH₂-C₆H₁₀-CH₂- (any isomer); and phenyl (ortho or para).

6. A process according to any one of claims 1-5, characterised in that R³OOH is a compound selected from the group consisting of tert-butyl hydroperoxide, tert-amylhydroperoxide, tert-hexylhydroperoxide (all isomers), tert-heptylhydroperoxide (all isomers), 2,4,4-trimethylpentyl-2- hydroperoxide, α-cumylhydroperoxide, hydrogenated α- cumylhydroperoxide, 1 ,1-dimethyl-3-hydroxybutyl-1 -hydroperoxide, p- menthylhydroperoxide, 2,5-dimethyl-2,5dihydroperoxy hexane, 2,5-dimethyl-

2,5dihydroperoxy hexyne, (meta and/or para) di(hydroperoxyisopropyl)benzene, and ketone hydroperoxides.

7. A process according to any one of claims 2-6, characterised in that the basic catalyst is an alkaline (earth) hydroxide or an alkaline (earth) oxide, preferably calcium hydroxide, sodium hydroxide, calcium oxide or sodium oxide.

8. A process according to any one of claims 2 to 7, characterised in that the phase transfer catalyst is methyl tri-capryl ammonium chloride.

9. A process according to any one of claims 1 to 8, characterised in that the molar ratio of the vinyl groups in the (di)carboxylic acid (di)vinyl ester to the hydroperoxide groups of the alkylhydroperoxide is in the range of 0.7 : 1.0 to 1.2 : 1.0.

10. A process according to any one of claims 2 to 9, characterised in that the molar ratio of the vinyl groups in the (di)carboxylic acid (di)vinyl ester to the basic catalyst is in the range of 3 : 1 to 25 : 1.

11. A process according to one of more of claims 1 to 10, characterised in that the reaction is carried out at atmospheric pressure or lower and the acetaldehyde is removed from the perester by distillation.