JP2016210699A - Manufacturing method of 4-hydroxy benzoic acid long chain ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing 4-hydroxy benzoic acid long chain ester represented by the formula (3) at high purity by suppressing generation of byproducts.SOLUTION: By transesterification of 4-hydroxy benzoic acid short chain ester and a long chain alcohol by using a metal catalyst as a catalyst, generation of byproducts is suppressed and 4-hydroxy benzoic acid long chain ester can be manufactured at high purity. (In the formula, n represents an integer of 15 to 23.)SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a 4-hydroxybenzoic acid long chain ester.

  4-Hydroxybenzoic acid long-chain ester has a structure having a hydroxyl group and a hydrophobic group, and uses such as a plasticizer, a compatibilizing agent and a surfactant have been proposed because of its structural characteristics.

  In general, esterification of a compound is performed by reacting a raw material carboxylic acid and an alcohol in the presence of a protonic acid catalyst such as sulfuric acid, and removing the catalyst and unreacted carboxylic acid from the resulting reaction solution, and if necessary, crystallizing. A method of producing by purification such as precipitation or distillation is known (Patent Document 1).

  Regarding esterification of 4-hydroxybenzoic acid, it is known that 4-hydroxybenzoic acid short-chain ester is obtained relatively easily by reaction with a short-chain alcohol having 1 to 6 carbon atoms.

  However, when 4-hydroxybenzoic acid is reacted with a long-chain alcohol having 16 or more carbon atoms to obtain 4-hydroxybenzoic acid long-chain ester, the reaction is similarly performed in the presence of a protonic acid catalyst. In addition, by-products such as ethers obtained by dimerizing long-chain alcohols and sulfates by reaction of long-chain alcohols with protonic acid catalysts are inevitable.

  Since these by-products have physical properties similar to the target 4-hydroxybenzoic acid long chain ester, it is difficult to remove by crystallization or distillation, and high purity 4-hydroxybenzoic acid long chain ester There was a problem that could not be obtained.

JP 2014-108928 A

  The objective of this invention is providing the manufacturing method of 4-hydroxy benzoic acid long chain ester by which the production | generation of the by-product was suppressed. Another object of the present invention is to provide a method for producing a high purity 4-hydroxybenzoic acid long chain ester.

  As a result of intensive studies on a method for producing 4-hydroxybenzoic acid long-chain ester, the present inventors have used a metal catalyst as a catalyst, and a so-called transesterification reaction between 4-hydroxybenzoic acid short-chain ester and long-chain alcohol. As a result, it was found that by-product formation was suppressed, and a high-purity 4-hydroxybenzoic acid long-chain ester was obtained, and the present invention was completed.

（式中、ｍは１〜１１の整数を示し、ｎは１５〜２３の整数を示す。） That is, the present invention includes a step of reacting a 4-hydroxybenzoic acid short chain ester represented by the formula (1) with an aliphatic alcohol represented by the formula (2) in the presence of a metal catalyst. A method for producing a 4-hydroxybenzoic acid long chain ester represented by 3) is provided.

(In the formula, m represents an integer of 1 to 11, and n represents an integer of 15 to 23.)

According to the present invention, it is possible to suppress the formation of by-products such as ethers in which long-chain alcohols are dimerized and sulfate esters in which long-chain alcohols are reacted with catalysts, which are by-produced in normal esterification reactions, and have high purity. 4-hydroxybenzoic acid long chain ester can be obtained.
Furthermore, according to the present invention, a higher purity 4-hydroxybenzoic acid long chain ester can be obtained by a simple method without complicated purification.

  In the present invention, the 4-hydroxybenzoic acid short-chain ester represented by the formula (1) as a starting material has 4-hydroxybenzoic acid and a linear or branched carbon atom having 1 to 11 carbon atoms. It is an ester form with alcohol.

（ｍは１〜１１の整数を表す） Specific examples of the 4-hydroxybenzoic acid short chain ester represented by the formula (1) include methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, 4-hydroxybenzoate butyl, 4-hydroxybenzoate isobutyl, 4-hydroxybenzoate pentyl, 4-hydroxybenzoate hexyl, 4-hydroxybenzoate heptyl, 4-hydroxybenzoate octyl, 4-hydroxybenzoate nonatinyl, Examples include decyl 4-hydroxybenzoate, undecyl 4-hydroxybenzoate, and 2-ethylhexyl 4-hydroxybenzoate.

(M represents an integer of 1 to 11)

  Among these, in terms of easy availability and reactivity, methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate and Isobutyl 4-hydroxybenzoate is preferable, and methyl 4-hydroxybenzoate is more preferable because it is particularly excellent in reactivity.

  As the 4-hydroxybenzoic acid short chain ester used in the present invention, a commercially available one may be used, and 4-hydroxybenzoic acid and an aliphatic alcohol having 1 to 11 carbon atoms may be used as a proton acid catalyst. You may use what was obtained by the general esterification reaction made to react in presence.

（ｎは１５〜２３の整数を表す）
で表される炭素原子数１６〜２４の脂肪族アルコールである。その具体的としては、ヘキサデカノール、ヘプタデカノール、オクタデカノール、ノナデカノール、イコサノール、ヘンイコサノール、ドコサノール、トリコサノールおよびテトラコサノールからなる群から選択される１種以上が挙げられる。 The aliphatic alcohol used in the present invention has the formula (2):

(N represents an integer of 15 to 23)
Is an aliphatic alcohol having 16 to 24 carbon atoms. Specific examples thereof include one or more selected from the group consisting of hexadecanol, heptadecanol, octadecanol, nonadecanol, icosanol, heicosanol, docosanol, tricosanol and tetracosanol.

  As the aliphatic alcohol used in the present invention, commercially available products may be used, or those produced by methods known to those skilled in the art may be used.

  The aliphatic alcohol used in the present invention is 0.1 to 3 mol, preferably 0.5 to 1.5 mol, more preferably 0.8 to 1 mol per mol of 4-hydroxybenzoic acid short chain ester. .2 mol, particularly preferably 0.9 to 0.98 mol is preferably reacted.

  When the amount of the aliphatic alcohol is less than 0.1 mol with respect to 1 mol of 4-hydroxybenzoic acid short chain ester, it tends to cause a by-product reaction, and 4-hydroxybenzoic acid short chain ester becomes excessive. It is a waste of raw materials. When the amount of the aliphatic alcohol exceeds 3 mol, an excessive amount of the aliphatic alcohol remains and the purity tends to be lowered.

  In the present invention, in the reaction of 4-hydroxybenzoic acid short-chain ester with an aliphatic alcohol having 16 to 24 carbon atoms, a dimerized ether form of long-chain alcohol or long-chain alcohol is obtained by the presence of a metal catalyst. The production of by-products such as sulfate ester due to the reaction between the catalyst and the catalyst can be suppressed, and a high-purity 4-hydroxybenzoic acid long chain ester can be obtained.

  Examples of the metal catalyst used in the present invention include one or more selected from the group consisting of a titanium-based catalyst, a tin-based catalyst, an antimony-based catalyst, and a zirconium-based catalyst, but are excellent in availability and reactivity. Thus, a titanium-based catalyst is preferably used.

  Specific examples of the titanium-based catalyst include tetramethoxy titanium, tetraethoxy titanium, tetra n-propoxy titanium, tetraisopropoxy titanium, tetra n-butoxy titanium, tetraisobutoxy titanium, tetra 2-ethylhexoxy titanium, and tetraoctade. Soxy titanium is mentioned. Tetraisopropoxy titanium is preferable in terms of excellent reactivity and availability.

  Specific examples of the tin-based catalyst include monobutyltin oxide, dibutyltin oxide, dibutyltin laurate, dioctyltin laurate and dibutyldiisopropoxytin. Monobutyltin oxide and dibutyltin oxide are preferable in terms of excellent reactivity and availability.

  Specific examples of the antimony catalyst include antimony acetate, antimony trioxide, diantimony pentoxide, trimethoxyantimony, triethoxyantimony, tri-n-propoxyantimony, and triphenylantimony. Antimony acetate is preferred because of its excellent reactivity and availability.

  Specific examples of the zirconium-based catalyst include tetramethoxy zirconium, tetraethoxy zirconium, tetra n-propoxy zirconium, tetraisopropoxy zirconium, tetra n-butoxy zirconium, tetraisobutoxy zirconium, tetra 2-ethylhexoxy zirconium, tetraoctade. Soxyzirconium and zirconium acetate oxide are mentioned. Tetra n-butoxyzirconium is preferable in terms of excellent reactivity and availability.

These catalysts may be used alone or in combination of two or more.
The amount of the metal catalyst used in the present invention is 0.1 to 10 parts by weight, preferably 0.5 to 7 parts by weight, more preferably 1 to 5 parts per 100 parts by weight of the 4-hydroxybenzoic acid short chain ester. It should be part by weight.

  When the amount of the metal catalyst is less than 0.1 parts by weight with respect to 100 parts by weight of 4-hydroxybenzoic acid short chain ester, the reaction tends to not proceed sufficiently. When the amount of the metal catalyst exceeds 10 parts by weight, by-products such as dimerized ethers of aliphatic alcohols tend to be generated, and this is economically disadvantageous.

  The reaction between the 4-hydroxybenzoic acid short-chain ester and the aliphatic alcohol having 16 to 24 carbon atoms is preferably performed at a temperature of 120 to 200 ° C, more preferably at a temperature of 150 to 180 ° C. preferable. When the reaction temperature is lower than 120 ° C, the reaction tends not to proceed sufficiently. When the reaction temperature is higher than 200 ° C, a by-product tends to be generated and energy is lost.

  The reaction time is not particularly limited because it varies depending on conditions such as the reaction temperature, but is appropriately selected from 1 to 20 hours, preferably 3 to 15 hours, more preferably 5 to 10 hours.

  In the present invention, the reaction between the 4-hydroxybenzoic acid short chain ester and the aliphatic alcohol having 16 to 24 carbon atoms is preferably carried out under a nitrogen stream or bubbling or under reduced pressure. By reacting under such conditions, it is possible to avoid reaction inhibition and catalyst deactivation due to oxygen and moisture, easily remove short-chain alcohol by-produced from the reaction, and proceed the reaction smoothly. Become.

（式中、ｎは１５〜２３の整数を示す）
で表される４−ヒドロキシ安息香酸長鎖エステルが得られる。 By separating and recovering the reaction solution obtained by the transesterification reaction by a known method such as liquid separation, recrystallization, and preparative operation, the formula (3):

(In the formula, n represents an integer of 15 to 23)
4-hydroxybenzoic acid long chain ester represented by the following formula is obtained.

  Specifically, as the 4-hydroxybenzoic acid long chain ester represented by the formula (3), hexadecyl 4-hydroxybenzoate, heptadecyl 4-hydroxybenzoate, octadecyl 4-hydroxybenzoate, 4-hydroxybenzoic acid Nonadecyl, icosyl 4-hydroxybenzoate, heicosyl 4-hydroxybenzoate, docosyl 4-hydroxybenzoate, tricosyl 4-hydroxybenzoate and tetracosyl 4-hydroxybenzoate.

  In this way, a high-purity 4-hydroxybenzoic acid long-chain ester in which the production of by-products is suppressed is obtained, but the obtained 4-hydroxybenzoic acid long-chain ester is purified for further purification. Can be used for operation. The purification method is not particularly limited. For example, the obtained 4-hydroxybenzoic acid long-chain ester is melted or diluted with a non-water-soluble solvent, and then extracted with water or alkaline water. Examples thereof include a method of solidifying the product and suspension washing with water or alkaline water. These purification methods can be performed alone or in combination.

  In this invention, it is preferable to refine | purify after removing the metal catalyst which remains in the reaction liquid obtained by transesterification with 4-hydroxy benzoic acid short chain ester and aliphatic alcohol. In this case, the catalyst removal and purification are not particularly limited, but an acid aqueous solution was added to the reaction solution obtained by the reaction of 4-hydroxybenzoic acid short-chain ester with an aliphatic alcohol to separate into an organic layer and an aqueous layer. Then, it can carry out by the process of extracting an organic layer, and the process of adding an organic solvent to the extracted organic layer, and crystallizing.

  The step of extracting the organic layer after adding an aqueous acid solution to the reaction solution and separating the organic layer and the aqueous layer (hereinafter referred to as the extraction step) is specifically performed after adding the aqueous acid solution to the reaction solution and stirring. Under heating, the organic substance in the reaction solution is melted, and the catalyst is deactivated by continuing stirring. Thereafter, the reaction system is allowed to stand to separate into an organic layer and an aqueous layer, and the organic layer is recovered.

  The solvent used for the acid aqueous solution in the extraction step is preferably a mixture of water and a lower alcohol. As a lower alcohol, 1 or more types selected from the group which consists of methanol, ethanol, 1-propanol, and 2-propanol are mentioned, Among these, methanol is preferably used at the point which is excellent in a yield and economical efficiency.

  The weight ratio of water to lower alcohol (water / lower alcohol) is not particularly limited because it varies depending on the type of alcohol used, but it should be 5/5 to 2/8, preferably 4/6 to 2/8. .

  When the weight ratio of water and lower alcohol exceeds 5/5, the reaction solution and the acid aqueous solution are emulsified, and the catalyst tends not to be sufficiently removed. When the weight ratio of water to lower alcohol is less than 2/8, the reaction Since the entire system becomes a uniform solution, there is a tendency that the catalyst cannot be sufficiently removed.

  The acid used in the acid aqueous solution inactivates the catalyst, and specifically includes at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, carboxylic acid and sulfonic acid. It is done. Among these, phosphoric acid is preferable in that the color tone of the obtained 4-hydroxybenzoic acid long chain ester is improved.

  The amount of the solvent and acid used in the aqueous acid solution is 0.1 to 10% by weight, preferably 0.5 to 8% by weight, more preferably 1 to 5% by weight, based on the solvent.

  When the amount of the acid is less than 0.1% by weight with respect to the solvent, the catalyst tends not to be sufficiently removed, and when it exceeds 10% by weight, the acid tends to remain as an impurity.

  The amount of the acid aqueous solution is 3 times or more, preferably 5 times or more, by weight of the raw material 4-hydroxybenzoic acid short chain ester. When the amount of the aqueous acid solution is less than 3 times the weight, the liquid separation property of the organic layer and the aqueous layer is deteriorated, and the catalyst tends not to be sufficiently removed.

  In the extraction step, in order to melt the organic matter in the reaction system, the mixture is heated to 50 ° C. or higher, preferably 60 ° C. or higher, and stirring is continued at that temperature to deactivate the catalyst. The reaction system is allowed to stand until and are sufficiently separated, and the separated organic layer is recovered.

  The organic layer recovered in the extraction step is then subjected to a step of crystallization by adding an organic solvent to the extracted organic layer (hereinafter referred to as a crystallization step). In the crystallization step, an organic solvent is added to the organic layer, heated and dissolved, and then cooled to cool the target product. A high-purity 4-hydroxybenzoic acid long-chain ester can be obtained by solid-liquid separation of the precipitated crystals by filtration or the like, washing and drying.

  Examples of the organic solvent used in the crystallization process include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and ethylene glycol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, methyl acetate, ethyl acetate, and acetic acid. Esters such as propyl and butyl acetate, amide compounds such as N, N′-dimethylformamide, N-methylpyrrolidone and pyridine, hydrocarbon compounds such as pentane, hexane, heptane, benzene, toluene, xylene and cyclohexane, chloroform And organic halogens such as dichloromethane, ethers such as diisopropyl ether, tetrahydrofuran and 1,4-dioxane. Among these, in terms of excellent industrial productivity such as availability and drying efficiency, methanol, ethanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, propyl acetate, Hexane, heptane, toluene and xylene are preferred, and methanol is particularly preferred from the viewpoint of excellent yield.

  The amount of the organic solvent used in the crystallization step is not particularly limited because it varies depending on the type of solvent used, but it is 1 to 20 times by weight, preferably 3 to 10 times the weight of the raw 4-hydroxybenzoic acid short chain ester. The weight, more preferably 5 to 7 times the weight is good.

  When the amount of the organic solvent is less than 1 times the weight, stirring failure tends to occur at the time of crystallization. When the amount exceeds 20 times the weight, the yield tends to decrease and it is economically disadvantageous.

  The crystallization step is performed by adding an organic solvent, heating to completely dissolve the organic matter in the organic layer, and then slowly cooling and crystallization while continuing stirring.

  When a supersaturation phenomenon occurs during crystallization, a seed crystal may be added as appropriate to promote crystallization.

  Crystals precipitated in the crystallization step are subjected to solid-liquid separation by conventional means such as filtration, and the target 4-hydroxybenzoic acid long chain ester is recovered. In the solid-liquid separation, it is preferable to wash the crystals by appropriately pouring an organic solvent. As the organic solvent used in the solid-liquid separation, the same organic solvent used in the crystallization step is used.

  Crystals recovered by solid-liquid separation can be dried in a crystalline state under reduced pressure at a temperature of 50 ° C. or lower, or heated to 50 ° C. or higher to melt the crystals, and then the solvent is distilled off. High purity 4-hydroxybenzoic acid long chain ester can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this.

[Conversion rate and residual rate]
The molar ratio of the production amount of each component to the charged amount of the aliphatic alcohol was defined as the conversion rate. Further, the molar ratio of the remaining amount to the charged amount of each starting material was defined as the remaining rate.
The production amount of each component and the remaining amount of each starting material were determined by quantitative analysis by high performance liquid chromatography (HLPC) and gas chromatography (GC) under the following conditions.

[High performance liquid chromatography (HLPC)]
Equipment: Waters Alliance 2487/2996
Column model number: L-Column
Flow rate: 1.0 mL / min Solvent ratio: H ₂ O (pH 2.3) / CH ₃ OH = 58/42 (30 minutes) → 5 minutes → 10/90 (55 minutes), gradient analysis Wavelength: 229 nm / 254 nm
Column temperature: 40 ° C

[Gas chromatography (GC)]
Equipment: GC-2014 / GC-14A manufactured by Shimadzu Corporation
Column model number: G-100
Injection volume: 1.0 μL
Oven temperature: 310 ° C
Carrier gas: Helium Detector: FID

Example 1
179 g of hexadecanol (CeOH) was added to a 1 L four-necked flask equipped with a stirrer, a temperature sensor, and a Dean-Stark apparatus, and the mixture was heated to 70 ° C. and melted under a nitrogen stream. Next, 125 g of methyl 4-hydroxybenzoate (MOB) and 3.76 g of tetraisopropoxytitanium (TIPT) as a catalyst were added, the temperature was raised to 160 ° C. over 1 hour, and the reaction was performed at the same temperature for 6 hours.

When the reaction solution was quantitatively analyzed by high performance liquid chromatography (HPLC) and gas chromatography (GC), the conversion rate from the charged CeOH was 96.2 mol% of hexadecyl 4-hydroxybenzoate (CEPB) (91 0.5 wt%), and MOB 8.2 mol% (3.5 wt%) and CeOH 2.6 mol% (1.6 wt%) remained. Further, generation of is dicetyl ether _(Ce 2 O) and sulfuric acid ester ethers body p- toluenesulfonic acid hexadecyl (PTS-Ce) was not confirmed.

Comparative Example 1
258 g of CeOH was added to a 1 L four-necked flask equipped with a stirrer, a temperature sensor, and a Dean-Stark apparatus, and the mixture was heated to 70 ° C. and melted under a nitrogen stream. Next, 150 g of 4-hydroxybenzoic acid (POB), 5.0 g of p-toluenesulfonic acid monohydrate and 2.4 g of hypophosphorous acid were added, and the temperature was raised to 130 ° C. over 1 hour. Reacted for hours. When the reaction solution was quantitatively analyzed by HPLC and GC, the conversion rate from the charged CeOH was 92.9 mol% (86.1 wt%) of CEPB, 8.7 mol% (2.8 wt%) of POB and CeOH 3.4 mol% (1.4 wt%) remained. Moreover, the conversion rate of Ce ₂ O which is an ether form is 2.5 mol% (1.8 wt%), the conversion rate of PTS-Ce which is a sulfate ester is 0.81 mol% (1.0 wt%), By-product formation was confirmed.

Example 2
The reaction was conducted in the same manner as in Example 1 except that 263 g of tetracosanol (TcOH) was added as a raw material instead of CeOH. The conversion from the charged TcOH was 94.8 mol% (89.1 wt%) tetracosyl 4-hydroxybenzoate (TCPB), 9.5 mol% (3.9 wt%) MOB and 3.8 mol% TcOH (2 0.5% by weight) remained. Further, generation of a di tetracosyl ether _(Tc 2 O) and sulfuric acid ester ethers body p- toluenesulfonic acid tetracosyl (PTS-Tc) was observed.

Comparative Example 2
The reaction was performed in the same manner as in Comparative Example 1 except that 347 g of tetracosanol (TcOH) was added as a raw material instead of CeOH. The conversion rate from the charged TcOH was TCPB 92.3 mol% (88.6 wt%), and POB 9.0 mol% (3.2 wt%) and TcOH 3.7 mol% (2.5 wt%) remained. Further, the conversion rate of Tc ₂ O which is an ether form is 2.7 mol% (1.8 wt%), the conversion rate of PTS-Tc which is a sulfate ester is 0.90 mol% (1.0 wt%), By-product formation was confirmed.

Example 3
The reaction was conducted in the same manner as in Example 1 except that butyl 4-hydroxybenzoate (NBE) was added as a raw material instead of MOB. The CEPB conversion from the charged CeOH was 70.3 mol%, and NBE 43.8 mol% and CeOH 29.7 mol% remained. Further, generation of dicetyl ether (Ce 2 _O), and are sulfuric ester p- toluenesulfonic acid hexadecyl ethers member was not confirmed.

Examples 4-6
The reaction was performed in the same manner as in Example 1 except that CeOH was set to the equivalent shown in Table 1, the reaction temperature was 180 ° C., and the reaction time was 4 hours. The results are shown in Table 1.

MOB: methyl 4-hydroxybenzoate CeOH: to Kisadekanoru CEPB: 4-hydroxybenzoic acid hexadecyl _Ce 2 O: dicetyl ether PTS-Ce: p-toluenesulfonic acid hexadecyl CeOH equivalent: mol ratio of CeOH charged amount for material MOB remaining Rate: mol% of each starting material remaining relative to the charge of each starting material
Conversion rate: mol% of each component generated with respect to the amount of CeOH charged
N. D. : Below detection limit

Examples 7-10
The reaction was carried out in the same manner as in Example 1 except that the conditions shown in Table 2 were used for the CeOH equivalent, catalyst, catalyst amount, reaction temperature, and reaction time. The results are shown in Table 2 together with Example 1.

TIPT: Tetraisopropoxytitanium PTS · H ₂ O: p-Toluenesulfonic acid monohydrate MBTO: Monobutyltin oxide DBTO: Dibutyltin oxide Sb (OAc) ₃ : Antimony acetate Zr (OBu) ₄ : Tetrabutoxyzirconium

Examples 11-13
The reaction was performed in the same manner as in Example 1 except that the amount of catalyst was changed to the amount shown in Table 3. The results are shown in Table 3.

Examples 14-16
The reaction was performed in the same manner as in Example 1 except that the reaction temperature was changed to the temperature shown in Table 4. The results are shown in Table 4.

Examples 17-19
The reaction was performed in the same manner as in Example 1 except that the reaction time was set as shown in Table 5. The results are shown in Table 5.

Example 20
A 1 L bottomed four-necked flask equipped with a stirrer, temperature sensor and cooling pipe and provided with a discharge port with a cock at the bottom was charged with a mixed solution of 372 g of water, 875 g of methanol and 15 g of 85 wt% aqueous phosphoric acid . Next, 273 g of the reaction solution obtained in Example 1 was cooled to 110 ° C. and then added to the mixed solution. After the solution was heated to 60 ° C. and melted, the solution was stirred at the same temperature for 1 hour, the stirring was stopped and the mixture was allowed to stand at the same temperature for 1 hour to separate into an organic layer and an aqueous layer. Was recovered from the bottom outlet.

  688 g of methanol was added to the collected organic layer, and the mixture was heated again to 60 ° C. and dissolved, and then cooled to 15 ° C. for crystallization. The solid matter obtained by crystallization was taken out by filtration, washed with 230 g of methanol, and then dried at 45 ° C. and 10 mmHg to obtain 236 g of crystals.

When the obtained crystals were quantitatively analyzed by HPLC and GC, the purity was 99.4% by weight, CeOH 0.2% by weight, CE (PB) ₂ 0.8% by weight, titanium content 1.2 ppm. Met. Further, dicetyl ether (Ce ₂ O) as an ether form and hexadecyl p-toluenesulfonate as a sulfate ester were not detected.

Comparative Example 3
A mixed solution of 450 g of water, 1050 g of methanol and 4.5 g of 48 wt% sodium hydroxide was added to a 2 L bottomed four-necked flask equipped with a stirrer, temperature sensor and cooling pipe and provided with a discharge port with a cock at the bottom. Prepared. Next, 386 g of the reaction solution obtained in Comparative Example 1 was cooled to 110 ° C. and then added to the mixed solution. The solution was heated to 60 ° C. and melted, and then stirred at the same temperature for 1 hour. The stirring was stopped and the mixture was allowed to stand at the same temperature for 1 hour to separate into an organic layer and an aqueous layer.

  The lower organic layer was recovered from the bottom outlet, 825 g of methanol was added to the recovered organic layer, and the mixture was again heated to 60 ° C. and dissolved, and then cooled to 15 ° C. for crystallization. The solid matter obtained by crystallization was taken out by filtration, washed with 300 g of methanol, and then dried under conditions of 45 ° C. and 10 mmHg to obtain 352 g of crystals.

When the obtained crystals were quantitatively analyzed by HPLC and GC, the purity was 94.3% by weight, POB 0.04% by weight, CeOH 0.5% by weight, CE (PB) ₂ 0.61% by weight, Ce ₂ O, which is an ether form, remained at 2.0% by weight.

Example 21
349 g of crystals were obtained in the same manner as in Example 20 except that 395 g of the reaction solution obtained in Example 2 was used. The obtained crystals were quantitatively analyzed by HPLC and GC. As a result, the purity was 98.0 wt%, TcOH 0.2 wt%, TC (PB) ₂ 1.5 wt%, and titanium content 1.8 ppm. In addition, Tc ₂ O as an ether form and PTS-Tc as a sulfate ester were not detected.

Comparative Example 4
480 g of crystals were obtained in the same manner as in Comparative Example 3 except that 520 g of the reaction solution obtained in Comparative Example 2 was used. When the obtained crystals were quantitatively analyzed by HPLC and GC, the purity was 94.0% by weight, POB 0.03% by weight, TcOH 0.6% by weight, TC (PB) ₂ 0.58% by weight, 2.4% by weight of Tc ₂ O, which is an ether form, remained.

  As described above, according to the present invention, high purity can be achieved without producing by-products such as an ether form obtained by dimerizing a long-chain alcohol as a starting material, and a sulfate ester by a reaction between a long-chain alcohol and a protonic acid catalyst. It can be seen that 4-hydroxybenzoic acid long-chain ester is obtained. Moreover, it is understood that 4-hydroxybenzoic acid short chain ester of higher purity can be obtained by removing the metal catalyst in the reaction solution and performing a purification operation.

Claims (6)

In the presence of a metal catalyst, represented by formula (3), comprising a step of reacting a 4-hydroxybenzoic acid short chain ester represented by formula (1) with an aliphatic alcohol represented by formula (2). 4-hydroxybenzoic acid long-chain ester production method.

(In the formula, m represents an integer of 1 to 11, and n represents an integer of 15 to 23.)   The production method according to claim 1, wherein the 4-hydroxybenzoic acid long chain ester represented by the formula (3) is hexadecyl 4-hydroxybenzoate.   The manufacturing method of Claim 1 or 2 whose 4-hydroxybenzoic acid short chain ester represented by Formula (1) is methyl 4-hydroxybenzoate.   The manufacturing method in any one of Claims 1-3 with which 0.1-3 mol of aliphatic alcohol is made to react with respect to 1 mol of 4-hydroxybenzoic acid short chain ester.   The manufacturing method in any one of Claims 1-4 which makes 0.1-10 weight part of metal catalysts exist with respect to 100 weight part of 4-hydroxybenzoic acid short chain ester.   The production method according to any one of claims 1 to 5, wherein the 4-hydroxybenzoic acid short-chain ester and the aliphatic alcohol are reacted at a temperature of 120 to 200 ° C.