JPH0466466B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for synthesizing carboxylic acid halohydrin esters, which are precursors of carboxylic acid glycidyl esters, which are important in the organic industry, by ring-opening addition of carboxylic acids to epihalohydrins. (Prior Art) Conventionally, it has been known that the reaction of adding a carboxylic acid to epihalohydrin to form a halohydrin ester can be carried out as shown in the following reaction formula () using, for example, a quaternary ammonium salt as a catalyst. However, it is generally not easy to remove the catalyst from the target product or purify the target product, and high-boiling by-products are produced, which is unsatisfactory especially from an industrial standpoint. (However, X is a halogen atom) (Object of the invention) The present invention provides a method for synthesizing a carboxylic acid halohydrin ester, which allows extremely easy isolation and purification of the target product. (Structure of the Invention) The present invention provides an organic tin compound selected from the group (A) below and a complete or partial alkyl ester of a phosphoric acid selected from the group (B) below, in the ring-opening addition of a carboxylic acid to an epihalohydrin. This is a method for synthesizing a halohydrin ester of a carboxylic acid, which is characterized by the presence of a thermal condensation product of the above as a catalyst. Group (A); RaSnX _4-a (A-1) (However, in the above formula (A-1), R is an aliphatic or aromatic hydrocarbon group having 1 to 12 carbon atoms, and X is a halogen atom. (a is an integer from 1 to 3.) RbSnOc (A-2) (However, in the above formula (A-2), R is (A-
It is the same as R in formula 1). b is 1 or 2
, when b=1, c=3/2, and when b=2, c
=1. ) (B) group; (HO) ₃ P=O (B-1) The above catalysts used in the present invention are some of those already disclosed by the applicant as ring-opening polymerization catalysts for three-membered ring epoxides (for example, US Pat. No. 3,773,694).
No. Specification). Conventionally, it is known that the acid strength of organic tin compounds is usually extremely low, and their function as general acid catalysts is extremely low and almost unknown. On the other hand, the thermal condensation product of organotin-phosphoric acid alkyl ester of the present invention exhibits high acid strength, and can be used as an acid catalyst for reactions involving oxirane, as an organotin compound, and as a catalyst for high polymerization of oxirane. It also shows a unique function. Specific examples of the group (A) organotin compounds of the catalyst of the present invention include the following. Representative compounds belonging to _{the above} general formula (A-1) include ( _C2H5 ) _4Sn , ( _C2H5 ) _SnBr3 ,
(C ₂ H ₅ ) ₃ SnF, (CH ₃ ) ₃ SnCl, (C ₄ H ₉ ) ₃ SnCl,
(C ₆ H ₅ ) ₄ Sn, (C ₈ H ₁₉ ) ₃ SnCl, (CH ₃ ) ₃ SnBr,
(C ₄ H ₉ ) ₂ SnCl ₂ and the like. Compounds belonging to the above general formula (A-2) include (CH ₃ ) ₂ SnO, (C ₄ H ₉ ) ₂ SnO, (C ₈ H ₁₇ ) ₂ SnO,
Examples include (C ₆ H ₅ ) ₂ SnO, CH ₃ SnO _3/2 , and C ₄ H ₉ SnO _3/2 . In the present invention, specific examples of complete or partial alkyl esters of phosphoric acids of group (B) include the following. (C ₂ H ₅ ) ₃ PO ₄ , (C ₃ H ₇ ) ₃ PO ₄ , (C ₄ H ₉ ) ₃ PO ₄ ,
(C ₈ H ₁₇ ) ₃ PO ₄ , (C ₁₂ H ₂₅ ) ₃ PO ₄ , (C ₂ H ₅ ) ₂ HPO ₄ ,
( _{C4H9 ) 2HPO4 ,} ( _{C4H9 ) H2PO4 , ( C4H9 ) 4P2O7 ,}
(C ₄ H ₉ ) ₂ H ₂ P ₂ O _7In the present invention, the component (B) constituting the catalyst is (B)
A catalytic reaction product having a similar catalytic effect can also be obtained by directly adding a combination of component compounds capable of forming a catalytic reaction together with component (A) to the catalyst production reaction system. Examples of combinations of component compounds that can form such component (B) include (a) a combination of phosphorus oxyhalide and an alcohol having 1 to 12 carbon atoms and an epoxide; (b) a combination of the above general formula A combination of a phosphoric acid selected from (B-1) and (B-2) or a partial alkyl ester thereof and an alcohol having 1 to 12 carbon atoms or an epoxide (c) Phosphoric anhydride and an alcohol having 1 to 12 carbon atoms Examples include combinations with other groups. Examples of phosphorus oxyhalides in (a) above include POCl ₃ , POBr ₃ , POI ₃ , (C ₂ H ₅ O)P(O)Cl,
Examples include (C ₈ H ₁₇ O) ₂ P(O)Br. Examples of alcohols include CH ₃ OH, C ₂ H ₅ OH, C ₃ H ₉ OH, C ₄ H ₉ OH,
_C6H13OH , _{ClCH2 − CH2OH} , _HOCH2−
Examples of epoxides include CH ₂ OH.

【formula】

【formula】

【formula】

[Formula] etc. Examples of the alcohols and epoxides in the above (b) include those mentioned in the above (a). The most preferable phosphoric anhydride in (c) above is P ₂ O ₅ . Further, examples of alcohols include those mentioned in (a) above. The thermal condensation product used in the present invention is usually 100%
It is produced by mixing and heating component (A) and component (B) or a combination of component compounds capable of forming component (A) and component (B) at ~300°C. A solvent may be used if necessary. Components (A) and (B) are used so that the ratio of tin atoms to phosphorus atoms contained is usually in the range of 1:10 to 10:1. In the reaction product obtained by the thermal condensation reaction as described above, various relatively simple substances are generated and eliminated by the condensation reaction, depending on the type of components. The resulting condensate exhibits the desired activity at various stages of the degree of condensation. The optimal degree of condensation varies depending on the type and ratio of components (A) and (B), but can be easily determined experimentally. Generally, condensates are initially soluble in various solvents such as hexane, benzene, and ether, but become insolubilized as the condensation reaction progresses. Any of these condensates, insoluble or soluble, can be used as a catalyst for the ring-opening addition reaction of the present invention. In particular, when an insoluble thermal condensate is used, the catalyst can be separated by simply filtering the reaction mixture after the addition reaction and can be used again. Epihalohydrins applicable to the present invention are epifluorohydrin, epichlorohydrin, epibromohydrin and epiiodohydrin. Examples of the carboxylic acids used in the addition reaction in the present invention include saturated aliphatic carboxylic acids such as acetic acid, propionic acid, butyric acid, unsaturated aliphatic carboxylic acids such as acrylic acid and sorbic acid, benzoic acid, naphthoic acid, etc. The above-mentioned carboxylic acids having substituents such as aromatic carboxylic acids, chloroacetic acid, acetoacetic acid, naphthoxyacetic acid, cinnamic acid, methacrylic acid, and toluic acid can be mentioned. The ring-opening addition reaction of the present invention is achieved by bringing a mixture of epihalohydrin and carboxylic acid into contact with the above thermal condensation product. The amount of catalyst used, reaction temperature, etc. can be arbitrarily determined during implementation. The use of solvents is also optional. The carboxylic acid is usually used in excess of the epihalohydrin, and the ratio can be easily selected from a practical standpoint. (Effects of the Invention) The present invention enables ring-opening addition of carboxylic acid to epihalohydrin without causing side reactions such as the formation of high-boiling by-products, and because the catalyst can be completely and easily removed, it is possible to easily obtain the desired product with high The yield can be obtained,
It is particularly useful as a method for producing a highly pure carboxylic acid glycidyl ester precursor. (Examples) Examples 1 to 6 Ring-opening addition reactions with carboxylic acids as shown in Table 1 were carried out using epichlorohydrin. The catalyst used was a thermal condensation product of an organic tin compound and a phosphoric acid ester shown in (a) to (d) below. 10g of catalyst in a reactor equipped with a stirrer and reflux condenser
was heated at 150°C for 1 hour under nitrogen gas to dehumidify the catalyst. After cooling, 300 ml of dry benzene and 0.3 mol of carboxylic acid were added, followed by epichlorohydrin.
0.1 mol was added dropwise under stirring, and the mixture was allowed to react under reflux for a predetermined period of time. After the reaction was completed, saturated sodium bicarbonate solution was added to the reaction mixture to neutralize the unreacted carboxylic acid, and the catalyst was filtered off.
The organic layer was extracted and separated using methylene chloride. The extracted organic layer was washed with water, dried over magnesium sulfate, and concentrated. The resulting product was purified by distillation or silica gel chromatography. The yield shown in Table 1 is the total amount of the two types of isomers [(A) and (B)] shown in the reaction formula () above, and the value is Examples 3-5
was purified by silica gel chromatography (eluent:
Hexane/acetic acid = 20/1), Example 6 was calculated by recrystallization from a benzene-hexane mixed solvent. In addition, the product molar ratio is the above isomer (A) and
It is the molar ratio of (B), and its value was determined from nuclear magnetic resonance spectrum [ ¹ H-NMR (CCl ₄ )]. <Catalyst production method> Mix 0.1 mole of the organic tin compounds shown in (a) to (d) below and 0.2 mole of phosphoric acid ester and heat to 240 to 260 mol under a nitrogen stream.
Heated under stirring at 0C for 30 minutes. At this time, a large amount of desorption products were distilled out. After cooling, the residual pale yellow solid was crushed and used as a catalyst. The carbon content of the catalyst is (a) 30.12%, (b) 29.58%, and (c) in weight units, respectively.
30.51% and (d) 28.89%, and both of these catalysts are insoluble in hexane, benzene, and ether. (B) (C ₄ H ₉ ) ₂ SnO+2 (C ₄ H ₉ ) ₃ PO ₄ (B) (C ₄ H ₉ ) ₃ SnCl+2 (C ₄ H ₉ ) ₃ PO ₄ (C) (C ₆ H ₅ ) ₂ SnCl ₂ +2 (C ₂ H ₅ ) ₃ PO ₄ (d) CH ₃ SnO _3/2 +2 (C ₄ H ₉ ) ₂ HPO ₄

[Table] The assignments of the nuclear magnetic resonance spectra [ ¹ H-NMR (CCl ₄ )] of the products obtained in Examples 1 to 6 are shown below. In addition, in the following, Ac represents an acetyl group and Ph represents a phenyl group. Example 1 δ (ppm) 1.99 (s 3H CH ₃ -e) 3.44 - 4.05m 5.85H CH ₂ -a, c CH-b OH-d 4.84 (m 0.15H CH-f) b: f = 0.85: 0.15 Example 2 δ (ppm) 1.13 (t J=9Hz 3H CH ₃ -f) 2.30 (q J=9Hz 2H CH ₂ -e) 3.43 - 4.04m 5.86H CH ₂ -a, c CH-b OH-d 4.88 (m 0.14 H CH−g) b:g=0.86:0.14 Example 3 δ (ppm) 1.87 (s 3H CH ₃ -f) 3.41 - 4.14m 5.85H CH ₂ -a, c CH-b OH-d 4.90 (m 0.14H CH-g) 5.46 (br.s 1H CH ₂ -e ) 6.00 (br.s 1H CH ₂ −e) b:g=0.86:0.14 Example 4 δ (ppm) 3.45 ~ 4.21m 5.87H CH ₂ -a, c CH-b OH-d 4.98 (m 0.13H CH-h) 6.23 (d J=8Hz 1H CH-f) 7.03 ~ 7.37m 5H CH-g 7.50 (d J=8Hz 1H CH-e) b:h=0.87:0.13 Example 5 δ (ppm) 3.37 ~ 4.37m 5.89H CH ₂ -a, c CH-b OH-d 5.14 (m 0.11H CH-f) 7.06 ~ 8.81m 7H CH-e b: f = 0.89: 0.11 Example 6 δ (ppm) 2.30 (br.s 1H OH-d) 3.46 ~ 4.27m 5H CH ₂ , CH-a, b, c 4.66 (s 2H CH ₂ -e) 6.90 ~ 7.00m 7H CH-f In these examples The thus obtained mixture of halohydrin esters of carboxylic acids can be used as is for the synthesis of high purity glycidyl esters. Examples of producing glycidyl esters using the products obtained in Examples 2 to 5 are shown below. Application Examples 1 to 4 11.4 g of anhydrous potassium carbonate was placed in a flask equipped with a stirrer and a reflux condenser, and 20 ml of acetone was added and stirred. Then, a solution of 1.33 g of the products of Examples 2 to 5 dissolved in 30 ml of acetone was added dropwise, and the mixture was refluxed for 6 hours with vigorous stirring. After the reaction, the reaction solution was extracted with ether, the extract was washed with water, dried over magnesium sulfate, concentrated, and distilled to give glycidyl propionate (yield 72%), glycidyl methacrylate (yield 64%), and cinnabar, respectively. Glycidyl acid (90% yield) and glycidyl naphthoate (63% yield)
I got it.

Claims (1)

[Scope of Claims] 1. A complete or partial alkyl ester of an organotin compound selected from the group (A) below and a phosphoric acid selected from the group (B) below when performing ring-opening addition of a carboxylic acid to an epihalohydrin. 1. A method for synthesizing a halohydrin ester of a carboxylic acid, which comprises using a thermal condensation product of a carboxylic acid as a catalyst. Group (A) RaSnX _4-a (A-1) (However, in the above formula (A-1), R is an aliphatic or aromatic hydrocarbon group having 1 to 12 carbon atoms, and X is a halogen atom. (a is an integer from 1 to 3.) RbSnOc (A-2) (However, in the above formula (A-2), R is (A-
It is the same as R in formula 1). b is 1 or 2
, when b=1, c=3/2, and when b=2, c
=1. ) (B) group (HO) ₃ P=O (B-1)