Production process and purification process of 4-hydroxy-benzoic acid long chain ester

Abstract

The present invention relates to a production process of a 4-hydroxy-benzoic acid long chain ester, that includes a step of reacting a 4-hydroxy-benzoic acid short chain ester with an aliphatic alcohol in the presence of a metal catalyst. The present invention also relates to a purification process of a 4-hydroxy-benzoic acid long chain ester, that includes a step of adding an acid aqueous solution to a crude composition including the 4-hydroxy-benzoic acid long chain ester, separating the crude composition to an organic phase and a water phase and extracting the organic phase.

Claims

1. A production process of a 4-hydroxy-benzoic acid long chain ester represented by formula (3), comprising a step of reacting a 4-hydroxy-benzoic acid short chain ester represented by formula (1) with an aliphatic alcohol represented by formula (2) in the presence of a metal catalyst to obtain a crude composition containing the 4-hydroxy-benzoic acid long chain ester represented by formula (3), ##STR00006## wherein “m” represents an integer from 1 to 11 and “n” represents an integer from 15 to 23, and a step of adding an acid aqueous solution to the crude composition, separating the crude composition to an organic phase and a water phase and extracting the organic phase.

2. The production process according to claim 1, wherein in the step of extracting, a solvent contained in the acid aqueous solution is a mixture of water and a lower alcohol.

3. The production process according to claim 2, wherein the lower alcohol is one or more selected from a group consisting of methanol, ethanol, 1-propanol, and 2-propanol.

4. The production process according to claim 2, wherein a weight ratio of water and the lower alcohol is 5/5 to 2/8.

5. The production process according to claim 1, wherein in the step of extracting, an acid contained in the acid aqueous solution is one or more selected from a group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, carboxylic acid, and sulfonic acid.

6. The production process according to claim 1, wherein a content of the acid in the acid aqueous solution is 0.1 to 10% by weight.

7. The production process according to claim 1, further comprising a step of precipitating a crystal following addition of an organic solvent to the extracted organic phase.

8. The production process according to claim 7, wherein the organic solvent is methanol.

9. A purification process of a 4-hydroxy-benzoic acid long chain ester, comprising a step of adding an acid aqueous solution to a crude composition containing the 4-hydroxy-benzoic acid long chain ester represented by formula (3), separating the crude composition to an organic phase and a water phase and extracting the organic phase, ##STR00007## wherein “n” represents an integer from 15 to 23.

10. The purification process according to claim 9, wherein in the step of extracting, a solvent contained in the acid aqueous solution is a mixture of water and a lower alcohol.

11. The purification process according to claim 10, wherein the lower alcohol is one or more selected from a group consisting of methanol, ethanol, 1-propanol, and 2-propanol.

12. The purification process according to claim 10, wherein a weight ratio of water and the lower alcohol is 5/5 to 2/8.

13. The purification process according to claim 9, wherein in the step of extracting, an acid contained in the acid aqueous solution is one or more selected from a group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, carboxylic acid, and sulfonic acid.

14. The purification process according to claim 9, wherein a content of the acid in the acid aqueous solution is 0.1 to 10% by weight.

15. The purification process according to claim 9, further comprising a step of precipitating a crystal by adding an organic solvent to the extracted organic phase.

16. The purification process according to claim 15, wherein the organic solvent is methanol.

17. The production process according to claim 1, wherein the 4-hydroxy-benzoic acid long chain ester represented by formula (3) is hexadecyl 4-hydroxy-benzoate.

18. The production process according to claim 1, wherein the 4-hydroxy-benzoic acid short chain ester represented by formula (1) is methyl 4-hydroxy-benzoate.

19. The production process according to claim 1, wherein 0.1 to 3 mol of the aliphatic alcohol is reacted with 1 mol of the 4-hydroxy-benzoic acid short chain ester.

20. The production process according to claim 1, wherein 0.1 to 10 part(s) by weight of the metal catalyst is present relative to 100 parts by weight of the 4-hydroxy-benzoic acid short chain ester.

21. The production process according to claim 1, wherein the 4-hydroxy-benzoic acid short chain ester and the aliphatic alcohol are reacted at a temperature from 120 to 200° C.

22. The production process according to claim 1, wherein the 4-hydroxy-benzoic acid short chain ester and the aliphatic alcohol are reacted under a gas flow of an inert gas of 0.10 to 0.50 mL/min per 1 g of a total amount of the 4-hydroxy-benzoic acid short chain ester and the aliphatic alcohol.

23. The production process according to claim 22, wherein the inert gas is one or more selected from a group consisting of nitrogen, carbon dioxide, argon, helium, neon, xenon, and krypton.

24. The production process according to claim 1, wherein the metal catalyst is one or more selected from a group consisting of a titanium-based catalyst, a tin-based catalyst, an antimony-based catalyst, and a zirconium-based catalyst.

Description

EXAMPLES

Conversion Rate and Residual Rate

(1) The mol ratio of the generation amount of each component relative to the charged amount of the aliphatic alcohol was used as the conversion rate. The mol ratio of the residual amount relative to the charged amount of each starting material was used as the residual rate.

(2) The generation amount of each component and the residual amount of each starting material were acquired by quantitative analyses using high-performance liquid chromatography (HPLC) and gas chromatography (GC) under the conditions as below.

(3) [High-Performance Liquid Chromatography (HPLC)]

(4) Apparatus: Waters Alliance 2487/2996

(5) Column Model: L-Column

(6) Liquid Amount: 1.0 mL/min

(7) Solvent Ratio: H.sub.2O (pH 2.3)/CH.sub.3OH=58/42 (30 minutes).fwdarw.5 minutes.fwdarw.10/90 (55 minutes), gradient analysis

(8) Wavelength: 229 nm/254 nm

(9) Column Temperature: 40° C.

(10) [Gas Chromatography (GC)]

(11) Apparatus: Manufactured by Shimadzu Corporation, GC-2014/GC-14A

(12) Column Model: G-100

(13) Injection Amount: 1.0 μL

(14) Oven Temperature: 310° C.

(15) Carrier Gas: Helium

(16) Detector: FID

Example 1

(17) 179 g of hexadecanol (CeOH) was added into a 1-L four-necked flask including a stirrer, a temperature sensor, and a Dean-and-Stark apparatus, and the temperature thereof was increased up to 70° C. under a gas flow of nitrogen to melt the content. 125 g of methyl 4-hydroxy-benzoate (MOB) and 3.76 g of titanium tetraisopropoxy (TIPT) as a catalyst were added thereto and the temperature of the content was increased up to 160° C. taking one hour to react the content at the same temperature for 6 hours.

(18) Quantitative analyses were conducted for the reaction liquid using the HPLC and the GC. As a result, the conversion rate from the charged CeOH was 96.2 mol % (91.5% by weight) of hexadecyl 4-hydroxy-benzoate (CEPB), and 8.2 mol % (3.5% by weight) of MOB and 2.6 mol % (1.6% by weight) of CeOH remained. No generation was determined for dicetyl ether (Ce.sub.2O) which is an ether and hexadecyl-p-toluene-sulfonate (PTS-Ce) which is a sulfate ester.

Comparative Example 1

(19) 258 g of CeOH was added into a 1-L four-necked flask including a stirrer, a temperature sensor, and a Dean-and-Stark apparatus, and the temperature thereof was increased up to 70° C. under a gas flow of nitrogen to melt the content. 150 g of 4-hydroxy-benzoic acid (POB), 5.0 g of p-toluene-sulfonic acid monohydrate, and 2.4 g of hypophosphorus acid were added thereto and the temperature of the content was increased up to 130° C. taking one hour to react the content at the same temperature for 8 hours. Quantitative analyses were conducted for the reaction liquid using the HPLC and the GC and, as a result, the conversion rate from the charged CeOH was 92.9 mol % (86.1% by weight) for CEPB, and 8.7 mol % (2.8% by weight) of POB and 3.4 mol % (1.4% by weight) of CeOH remained. The conversion rate of Ce.sub.2O which is an ether was 2.5 mol % (1.8% by weight), and the conversion rate of PTS-Ce which is a sulfate ester was 0.81 mol % (1.0% by weight). Generation of side products was determined.

Example 2

(20) A reaction was conducted similarly to Example 1 except that 263 g of tetracosanol (TcOH) was added as a raw material instead of CeOH. The conversion rate from the charged TcOH was 94.8 mol % (89.1% by weight) of tetracosyl 4-hydroxy-benzoate (TCPB) and, 9.5 mol % (3.9% by weight) of MOB and 3.8 mol % (2.5% by weight) of TcOH remained. No generation was determined for ditetracosyl ether (Tc.sub.2O) which is an ether and tetracosyl p-toluene-sulfonate (PTS-Tc) which is a sulfate ester.

Comparative Example 2

(21) A reaction was conducted similarly to Comparative Example 1 except that 347 g of TcOH was added as a raw material instead of CeOH. The conversion rate from the charged TcOH was 92.3 mol % (88.6% by weight) of TCPB and, 9.0 mol % (3.2% by weight) of POB and 3.7 mol % (2.5% by weight) of TcOH remained. The conversion rate of Tc.sub.2O which is an ether was 2.7 mol % (1.8% by weight) and the conversion rate of PTS-Tc which is a sulfate ester was 0.90 mol % (1.0% by weight), and generation of side products was determined.

Example 3

(22) A reaction was conducted similarly to Example 1 except that butyl-4-hydroxy-benzoate (NBE) was added as a raw material instead of MOB. The CEPB conversion rate from the charged CeOH was 70.3 mol %, and 43.8 mol % of NBE and 29.7 mol % of CeOH remained. No generation was determined for Ce.sub.2O which is an ether and PTS-Ce which is a sulfate ester.

Examples 4 to 6

(23) A reaction was conducted similarly to Example 1 except that the amount of CeOH was set to be each of equivalent weights listed in Table 1, that the reaction temperature was set to be 180° C., and that the reaction time period was set to be 4 hours. The results are shown in Table 1.

(24) TABLE-US-00001 TABLE 1 CeOH Residual Rate Equivalent (mol %) Conversion Rate (mol %) Amount MOB CeOH CEPB Ce.sub.2O PTS-Ce Example 4 0.90 7.0 2.4 94.8 N.D. N.D. Example 5 0.95 8.6 3.4 94.8 N.D. N.D. Example 6 0.98 2.8 3.0 94.5 N.D. N.D. MOB: Methyl 4-hydroxy-benzoate CeOH: Hexadecanol CEPB: Hexadecyl 4-hydroxy-benzoate Ce.sub.2O: Dicetyl ether PTS-Ce: Hexadecyl p-toluene-sulfonate CeOH Equivalent Amount: The mol ratio of the charged amount of CeOH to the raw material MOB Residual Rate: The mol % of each remaining starting material relative to the charged amount of the starting material Conversion Rate: The mol % of each generated component relative to the charged amount of CeOH N.D.: An amount equal to or smaller than the detection limit amount

Examples 7 to 10

(25) A reaction was conducted similarly to Example 1 except that the conditions were set to be those listed in Table 2 concerning the CeOH equivalent weight, the catalyst, the amount of the catalyst, the reaction temperature, and the reaction time period. The results are shown in Table 2 with that of Example 1.

(26) TABLE-US-00002 TABLE 2 Amount of Catalyst CeOH Temper- Time (parts by Equivalent ature Period Catalyst weight) Amount (° C.) (h) Example 1 TIPT 3 0.90 160 6 Comparative PTS•H.sub.2O 3 0.98 130 8 Example 1 Example 7 MBTO 3 0.98 160 8 Example 8 DBTO 5 0.98 140 8 Example 9 Sb(OAc).sub.3 5 0.98 180 8 Example 10 Zr(OBu).sub.4 5 0.98 180 8 Residual Rate (mol %) Conversion Rate (mol %) MOB CeOH CEPB Ce.sub.2O PTS-Ce Example 1 8.2 2.6 96.2 N.D. N.D. Comparative — 3.4 92.9 2.5 0.81 Example 1 Example 7 5.9 2.4 96.3 N.D. N.D. Example 8 9.2 2.7 96.6 N.D. N.D. Example 9 6.1 2.7 95.7 N.D. N.D. Example 10 4.4 4.4 93.3 N.D. N.D. TIPT: Titanium tetraisopropoxide PTS•H.sub.2O: P-toluene-sulfonic acid monohydrate MBTO: Monobutyl-tin oxide DBTO: Dibutyl-tin oxide Sb(OAc).sub.3: Antimony acetate Zr(OBu).sub.4: Zirconium tetrabutoxide

Examples 11 to 13

(27) A reaction was conducted similarly to Example 1 except that the amount of the catalyst was set to be each of the amounts listed in Table 3. The results thereof are shown in Table 3.

(28) TABLE-US-00003 TABLE 3 Amount of Catalyst Residual Rate (parts by (mol %) Conversion Rate (mol %) weight) MOB CeOH CEPB Ce.sub.2O PTS-Ce Example 11 1 10.0 3.1 96.0 N.D. N.D. Example 12 2 6.8 2.2 96.3 N.D. N.D. Example 13 7 8.0 2.3 96.1 N.D. N.D.

Examples 14 to 16

(29) A reaction was conducted similarly to Example 1 except that the reaction temperature was set to be each of the temperatures listed in Table 4. The results thereof are shown in Table 4.

(30) TABLE-US-00004 TABLE 4 Residual Rate Temperature (mol %) Conversion Rate (mol %) (° C.) MOB CeOH CEPB Ce.sub.2O PTS-Ce Example 14 140 9.4 3.8 95.7 N.D. N.D. Example 15 150 8.8 2.8 96.1 N.D. N.D. Example 16 170 8.2 1.9 94.8 N.D. N.D.

Example 17 to 19

(31) A reaction was conducted similarly to Example 1 except that the reaction time period was set to be each of the time periods listed in Table 5. The results thereof are shown in Table 5.

(32) TABLE-US-00005 TABLE 5 Time Residual Rate Period (mol %) Conversion Rate (mol %) (h) MOB CeOH CEPB Ce.sub.2O PTS-Ce Example 17 2 18.0 9.8 90.0 N.D. N.D. Example 18 4 11.9 4.4 94.8 N.D. N.D. Example 19 8 6.3 1.7 96.7 N.D. N.D.

Example 20

(33) 185 g of CeOH was added into a 2-L four-necked flask including a stirrer, a temperature sensor, and a Dean-and-Stark apparatus, and the temperature thereof was increased up to 70° C. under a gas flow of nitrogen to melt the content. 129 g of MOB and 6.5 g of TIPT as a catalyst were added to the above and the temperature of the content was increased up to 150° C. taking one hour to react the content at the same temperature for 8 hours. During this, the flow of nitrogen in the reaction container was set to be 50 ml/min (0.16 ml/min per 1 g of the total amount of MOB and CeOH).

(34) Quantitative analyses were conducted for the reaction liquid obtained using the HPLC and the GC. The results thereof are shown in Table 6.

Example 21

(35) A reaction liquid was acquired similarly to Example 20 except that the flow of nitrogen was set to be 65 ml/min (0.20 ml/min per 1 g of the total amount of MOB and CeOH). Quantitative analyses were conducted for the reaction liquid obtained using the HPLC and the GC. The results thereof are shown in Table 6.

Example 22

(36) A reaction liquid was obtained similarly to Example 20 except that the flow of nitrogen was set to be 97 ml/min (0.30 ml/min per 1 g of the total amount of MOB and CeOH). Quantitative analyses were conducted for the reaction liquid obtained using the HPLC and the GC. The results thereof are shown in Table 6.

Comparative Example 3

(37) A reaction liquid was obtained similarly to Example 20 except that the flow of nitrogen was set to be 16 ml/min (0.05 ml/min per 1 g of the total amount of MOB and CeOH). Quantitative analyses were conducted for the reaction liquid obtained using the HPLC and the GC. The results thereof are shown in Table 6.

Example 23

(38) 832 g of CeOH was added into a 2-L four-necked flask including a stirrer, a temperature sensor, and a Dean-and-Stark apparatus, and the temperature thereof was increased up to 70° C. to melt the content. 580 g of MOB and 29.2 g of TIPT as a catalyst were added to the above and the temperature of the content was increased up to 150° C. taking one hour to react the content at the same temperature for 8 hours. During this, the flow of nitrogen in the reaction container was set to be 429 ml/min (0.30 ml/min per 1 g of the total amount of MOB and CeOH).

(39) Quantitative analyses were conducted for the reaction liquid obtained using the HPLC and the GC. The results thereof are shown in Table 6.

Example 24

(40) A reaction liquid was acquired similarly to Example 23 except that a 5-L four-neck flask was used as a reaction container. Quantitative analyses were conducted for the acquired reaction liquid using the HPLC and the GC. The results thereof are shown in Table 6.

Comparative Example 4

(41) A reaction liquid was acquired similarly to Example 23 except that the flow of nitrogen was set to be 71 ml/min (0.65 ml/min per 1 g of the total amount of MOB and CeOH). Quantitative analyses were conducted for the acquired reaction liquid using the HPLC and the GC. The results thereof are shown in Table 6.

Comparative Example 5

(42) A reaction liquid was acquired similarly to Example 23 except that the flow of nitrogen was set to be 923 ml/min (0.65 ml/min per 1 g of the total amount of MOB and CeOH). Quantitative analyses were conducted for the acquired reaction liquid using the HPLC and the GC. The results thereof are shown in Table 6.

(43) TABLE-US-00006 TABLE 6 Flow of Nitrogen (ml/min) Per 1 g of Total Amount Reaction MOB of MOB and CeOH Container Example 20 129 g 50 0.16 2 L Example 21 129 g 65 0.20 2 L Example 22 129 g 97 0.30 2 L Comparative 129 g 16 0.05 2 L Example 3 Example 23 580 g 429 0.30 2 L Example 24 580 g 429 0.30 5 L Comparative 580 g 71 0.05 2 L Example 4 Comparative 580 g 923 0.65 2 L Example 5 Residual Rate (mol %) Conversion Rate (mol %) MOB CEPB Ce.sub.2O Example 20 12.25 90.76 N.D. Example 21 11.31 92.07 N.D. Example 22 11.19 93.82 N.D. Comparative 31.66 72.89 N.D. Example 3 Example 23 11.45 92.46 N.D. Example 24 11.50 92.31 N.D. Comparative 35.13 68.24 N.D. Example 4 Comparative 10.83 92.19 0.28 Example 5 MOB: Methyl 4-hydroxy-benzoate CEPB: Hexadecyl 4-hydroxy-benzoate Ce.sub.2O: Dicetyl ether Residual Rate: The mol % of each remaining starting material relative to the charged amount of the starting material Conversion Rate: The mol % of each generated component relative to the charged amount of CeOH

(44) It can be seen as above that, according to the production process of the invention, the 4-hydroxy-benzoic acid long chain ester of high purity may be obtained without generating any side products such as an ether generated by dimerization of the long chain alcohol which is the starting material, a sulfate ester generated by a reaction of the long chain alcohol with the protic acid catalyst, and the like. It can also be seen that, according to the production process of the invention, the reactivity is not degraded even when the scale is increased.

(45) [Crude Composition 1]

(46) 179 g of CeOH was added into a 1-L four-necked flask including a stirrer, a temperature sensor, and a Dean-and-Stark apparatus, and the temperature thereof was increased up to 70° C. under a gas flow of nitrogen to melt the content. 125 g of MOB and 3.76 g of TIPT as a catalyst were added to the above and the temperature of the content was increased up to 160° C. taking one hour to react the content at the same temperature for 6 hours. As a result, crude composition 1 was obtained.

(47) Quantitative analyses were conducted for the crude composition 1 using the HPLC and the GC and, as a result, the conversion rate from the charged CeOH was 96.2 mol % for CEPB (91.5% by weight), and 8.2 mol % (3.5% by weight) of MOB and 2.6 mol % (1.6% by weight) of CeOH remained. No generation was determined for Ce.sub.2O which is an ether and PTS-Ce which is a sulfate ester.

(48) [Crude Composition 2]

(49) 263 g of TcOH was added into a 1-L four-necked flask including a stirrer, a temperature sensor, and a Dean-and-Stark apparatus, and the temperature thereof was increased up to 70° C. under a gas flow of nitrogen to melt the content. 125 g of MOB and 3.76 g of TIPT as a catalyst were added thereto and the temperature of the content was increased up to 160° C. taking one hour to react the content at the same temperature for 6 hours.

(50) Quantitative analyses were conducted for the crude composition 2 using the HPLC and the GC and, as a result, the conversion rate from the charged TcOH was 94.8 mol % (89.1% by weight) of TCPB, and 9.5 mol % (3.9% by weight) of MOB and 3.8 mol % (2.5% by weight) of TcOH remained. No generation was determined for Tc.sub.2O which is an ether and PTS-Tc which is a sulfate ester.

Example 25

(51) A mixed solution of 372 g of water, 875 g of methanol, and 15 g of phosphoric acid of 85% by weight was charged in a 2-L four-necked flask which had a discharge exit with a cock at its bottom and that included a stirrer, a temperature sensor, and a cooling pipe. 273 g of crude composition 1 was cooled to 110° C. and was thereafter added to the mixed solution. The temperature of the solution was increased up to 60° C. to melt the content and was thereafter stirred at the same temperature for 1 hour. The stirring was stopped and the solution was left untouched at the same temperature for 1 hour. An organic phase and a water phase were thereby separated from each other and the organic phase to be the lower phase was collected through the discharge exit in the bottom.

(52) 688 g of methanol was added to the collected organic phase and the temperature of the mixture was again increased up to 60° C. to dissolve the mixture, and the mixture was thereafter cooled to 15° C. to precipitate crystals. The solid matter obtained by the crystal precipitation was taken out using filtering, was washed using 230 g of methanol, and was thereafter dried under the conditions of 45° C. and 10 mmHg to obtain 236 g of crystals.

(53) Quantitative analyses were conducted for the acquired crystals using the HPLC and the GC and, as a result, the purity was 99.4% by weight, the crystals contained 0.2% by weight of CeOH and 0.8% by weight of CE(PB).sub.2, and the content of titanium was 1.2 ppm. No Ce.sub.2O which is an ether and no PTS-Ce which is a sulfate ester were detected.

Comparative Example 6

(54) A mixed solution of 450 g of water, 1,050 g of methanol, and 4.5 g of sodium hydroxide of 48% by weight was charged in a 2-L four-necked flask which had a discharge exit with a cock at its bottom and that included a stirrer, a temperature sensor, and a cooling pipe. 386 g of the crude composition 1 was cooled to 110° C. and was thereafter added to the mixed solution. The temperature of the solution was increased up to 60° C. to melt the content and was thereafter stirred at the same temperature for 1 hour. The stirring was stopped and the solution was left untouched at the same temperature for 1 hour. An organic phase and a water phase were thereby separated from each other.

(55) The organic phase to be the lower layer was collected through the discharge exit in the bottom. 825 g of methanol was added to the collected organic phase and the temperature thereof was again increased up to 60° C. to melt the content. The content was cooled to 15° C. to precipitate crystals. The solid matter acquired by the crystal precipitation was taken out using filtering, was washed using 300 g of methanol, and was thereafter dried under the conditions of 45° C. and 10 mmHg to acquire 352 g of crystals.

(56) Quantitative analyses were conducted for the acquired crystals using the HPLC and the GC and, as a result, the purity was 97.5% by weight, the crystals included 0.2% by weight of CeOH and 1.6% by weight of CE(PB).sub.2, and the content of titanium was 7,300 ppm. Neither Ce.sub.2O which is an ether nor PTS-Ce which is a sulfate ester was detected.

Examples 26 and 27

(57) The same operation was conducted as that of Example 25 except that the weight ratio of water and methanol used in the extraction was set to be each of those listed in Table 7. The liquid separation property was checked, and CEPB was acquired by those whose liquid separation processes were successful. The results are shown in Table 7.

(58) TABLE-US-00007 TABLE 7 Example/Comparative Example Example 26 Example 27 Water/Methanol Ratio 4/6 2/8 Liquid Separation Property Liquid was Liquid was able to be able to be separated. separated. CEPB MOB (% by weight)  0.03  0.01 Composition CeOH (% by weight) 0.2 0.2 CEPB (% by weight) 97.3  97.5  CE(PB).sub.2 (% by weight) 1.2 1.4 Ce.sub.2O (% by weight) N.D. N.D. POB (% by weight) N.D. N.D. Ti (ppm) 2.1 1.5 CE(PB).sub.2: 4-hydroxy-benzoic acid 4-(hexadecyloxycarbonyl)-phenyl ester Ce.sub.2O: Dicetyl ether POB: 4-hydroxy-benzoic acid Ti: Titanium

Examples 28 to 31

(59) The same operation was conducted as that of Example 25 except that the acid used in the extraction was changed to each of the acids listed in Table 8. The results are shown in Table 8.

(60) TABLE-US-00008 TABLE 8 Exam- Exam- Exam- Exam- ple 28 ple 29 ple 30 ple 31 Acid Hydro- Sulfuric Oxalic Phosphoric chloric Acid Acid Acid Acid Coloring of Crystal Yel- Yel- Yel- Sub- lowish lowish lowish stantially white CEPB MOB  0.05  0.03  0.02 N.D. Composition (% by weight) CeOH 0.4 0.3 0.3 0.2 (% by weight) CEPB 98.0  97.9  98.4  98.4  (% by weight) CE(PB).sub.2 1.4 1.4 1.4 1.8 (% by weight) Ce.sub.2O N.D. N.D. N.D. N.D. (% by weight) POB N.D. N.D. N.D. N.D. (% by weight) Ti (ppm) 2.3 2.6 2.6 1.2

Examples 32 to 34

(61) The same operation was conducted as that of Example 28 except that the amount of phosphoric acid used in the extraction was set to be each of those listed in Table 9.

(62) TABLE-US-00009 TABLE 9 Exam- Exam- Exam- ple 32 ple 33 ple 34 Amount of Phosphoric Acid 3   5   10   (% by weight) CEPB MOB (% by weight) N.D. N.D. N.D. Composition CeOH (% by weight) 0.2 0.2 0.2 CEPB (% by weight) 97.1  97.5  97.9  CE(PB).sub.2 (% by weight) 2.0 1.8 2.0 Ce.sub.2O (% by weight) N.D. N.D. N.D. POB (% by weight) N.D. N.D. N.D. Ti (ppm) 1.1 1.2 1.2

Example 35

(63) A mixed solution of 372 g of water, 875 g of methanol, and 15 g of phosphoric acid of 85% by weight was charged in a 2-L four-necked flask having a discharge exit with a cock at its bottom and including a stirrer, a temperature sensor, and a cooling pipe. 395 g of the crude composition 2 was cooled to 110° C. and was thereafter added to the mixed solution. The temperature of the solution was increased up to 60° C. to melt the content and was thereafter stirred at the same temperature for 1 hour. The stirring was stopped and the solution was left untouched at the same temperature for 1 hour. An organic phase and a water phase were thereby separated from each other. The organic phase to be the lower phase was collected through the discharge exit in the bottom.

(64) 688 g of methanol was added to the collected organic phase and the temperature thereof was again increased up to 60° C. to melt the content. The content was thereafter cooled to 15° C. to precipitate crystals. The solid matter acquired by the crystal precipitation was taken out using filtering, was washed using 230 g of methanol, and was thereafter dried under the conditions of 45° C. and 10 mmHg to obtain 349 g of crystals.

(65) Quantitative analyses were conducted for the resulted crystals using the HPLC and the GC and, as a result, the purity was 98.0% by weight, the crystals contained 0.2% by weight of TcOH and 1.5% by weight of Tc(PB).sub.2, and the content of titanium was 1.8 ppm. Neither Tc.sub.2O which is an ether nor PTS-Tc which is a sulfate ester was determined.

Comparative Example 7

(66) A mixed solution of 450 g of water, 1,050 g of methanol, and 4.5 g of sodium hydroxide of 48% by weight was charged in a 2-L four-necked bottom-removed flask having a discharge exit with a cock at its bottom and including a stirrer, a temperature sensor, and a cooling pipe. 474 g of the crude composition 2 was cooled to 110° C. and was thereafter added to the mixed solution. The temperature of the solution was increased up to 60° C. to melt the content and was thereafter stirred at the same temperature for 1 hour. The stirring was stopped and the solution was left untouched at the same temperature for 1 hour. An organic phase and a water phase were thereby separated from each other.

(67) The organic phase to be the lower phase was collected through the discharge exit in the bottom. 825 g of methanol was added to the collected organic phase and the temperature thereof was again increased up to 60° C. to dissolve the content. The content was thereafter cooled to 15° C. to precipitate crystals. The solid matter acquired by the crystal precipitation was taken out using filtering, was washed using 300 g of methanol, and was thereafter dried under the conditions of 45° C. and 10 mmHg to obtain 403 g of crystals.

(68) Quantitative analyses were conducted for the acquired crystals using the HPLC and the GC and, as a result, the purity was 97.1% by weight, the crystals contained 0.3% by weight of TcOH and 1.6% by weight of Tc(PB).sub.2, and the content of titanium was 7,800 ppm. Neither Tc.sub.2O which is an ether nor PTS-Tc which is a sulfate ester was determined.

(69) As above, according to the purification process of the invention, a 4-hydroxy-benzoic acid long chain ester of high purity can be obtained by adding an acid aqueous solution to a crude composition containing the 4-hydroxy-benzoic acid long chain ester to separate the organic phase and the water phase from each other, and extracting the organic phase.