WO2013035103A1 - Phenol c-alkylation process - Google Patents
Phenol c-alkylation process Download PDFInfo
- Publication number
- WO2013035103A1 WO2013035103A1 PCT/IN2011/000689 IN2011000689W WO2013035103A1 WO 2013035103 A1 WO2013035103 A1 WO 2013035103A1 IN 2011000689 W IN2011000689 W IN 2011000689W WO 2013035103 A1 WO2013035103 A1 WO 2013035103A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- acid
- phenol
- formula
- diisopropyl
- compound
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
- C07C37/50—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions decreasing the number of carbon atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/347—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups
- C07C51/353—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups by isomerisation; by change of size of the carbon skeleton
Definitions
- Phenol C-alkylation process FIELD OF THE INVENTION
- the invention relates to the process for producing ortho-isopropylated phenol.
- a typical example of ortho-isopropylated phenol is 2, 6-diisopropyl phenol, commonly known as Propofol, use as an anaesthetic for parenteral administration and such a use is become common in surgery. Since Propofol is administered by parenteral route, its purity degree must be very high.
- Several patents/patent applications have been filed for the preparation and purification of Propofol such as US2831898, US3367981, US3766276, US4103096, US5175376, US5414156, US4208537, US4275248, US4447657, US4538009 and US4559465.
- US2831898 discloses a process for producing 2, 6-diisopropyl phenol from propylene gas and phenol by Friedel-Crafts reaction at high pressure, high temperature and under nitrogen atmosphere with aluminum phenoxide, as a catalyst, prepared from alumina and phenol. But desired 2,6-diisopropyl phenol was obtained with very low yield along with other isomers and phenol derivatives such as 2,4-, 2,5-diisopropyl phenol, 2,4, 6- trisisopropyl phenol, 1- isopropoxy-2,4-diisopropyl benzene etc. The compounds formed in the reaction separated by fractional distillation, but this is very difficult due to small differences in the boiling points of the compound to be separated.
- US3367981 discloses the preparation method of a mixture of 2-isopropyl phenol and 2, 6- diisopropyl phenol by heating of a mixture of phenol and propylene gas to 314°C at nitrogen atmosphere in air tight vessel on a transitional alumina, as a catalyst, prepared by heating of an aluminum oxide hydrate and further adding a propylene gas at 310-312°C after reducing a resultant pressure.
- the yield of 2, 6-diidsopropyl phenol is low and the yield of 2-isopropyl phenol is high.
- US4447657 discloses the process for producing 2, 6- diisopropyl phenol by contacting isopropyl (2-isopropyl phenyl) ether with fluoride alumina under nitrogen pressure at 150°C and a 200 psi. This method uses the thermal rearrangement of alkyl phenyl ether. Drawback of this process is that 2, 6-diisopropyl phenol has low yield and 2-isopropyl phenol and 2, 4, 6-trisisopropyl phenol which are by-products have high yield.
- US5705039 discloses a process for the purification of impure 2,6-diisopropylphenol which comprises: a) subjecting the impure 2,6-diisopropylphenol to a first continuous distillation in a single distillation column in an inert environment to produce (i) a first overhead distillate of impurities boiling below the boiling point of 2,6-diisopropylphenol at the prevailing pressure and
- US5591311 discloses the process of purification of an impure 2, 6-diisopropylphenol mixture washing said mixture with aqueous alkali metal hydroxide solution and/or aqueous alkaline earth metal hydroxide solution in an inert atmosphere and separating the aqueous and organic phases, washing the resulting organic phase with water, and then subjecting the water- washed organic phase to distillation in an inert environment to recover purified 2, 6-diisopropylphenol.
- US5589598 describes a process for the purification of 2, 6-diisopropyl phenol by transformation of crude 2, 6-diisopropyl phenol into its ester with a carboxylic or sulphonic acid, followed by crystallization and hydrolysis.
- the object of the present invention is to provide an improved process for producing the 2, 6-diisopropyl phenol having high purity at low temperature and low pressure without producing by-products and therefore no requirement of the complicated separation procedure.
- An improved process for producing the 2, 6-diisopropyl phenol having high purity comprising of the alkylation of 4-hydroxybenzoic acid in presence of an acid to get the 4-hydroxy-3, 5- diisopropylbenzoic acid followed by decarboxylation in presence of high boiling solvents and a catalyst.
- the 2, 6-diisopropyl phenol commonly known as Propofol, is used as an anaesthetic for parenteral administration in surgery. .
- the object of the present invention is to provide a new, economical and highly effective process for producing high purity 2, 6-diisopropyl phenol.
- Another object of the present invention is to provide a process for the synthesis of 2, 6- diisopropyl phenol, the process comprising the reaction of 4-hydroxybenzoic acid with alkylating agent in presence of an acid to get 4-hydroxy-3, 5-diisopropylbenzoic acid followed by decarboxylation in presence of high boiling solvents and a catalyst to get the high purity 2, 6- diisopropylphenol.
- Yet another object of the invention is to provide a process to get the 2, 6-diisopropyl phenol with the purity greater than 99.9%.
- 6-diisopropyl phenol is obtained by the alkylation of 4-hydroxybenzoic acid in presence of an acid to get the 4-hydroxy-3, 5-diisopropylbenzoic acid followed by decarboxylation in presence of high boiling solvents and a catalyst.
- the process of the invention is depicted in following scheme-
- the process of the present invention comprises Friedel Crafts' s alkylation of 4-hydroxybenzoic acid in presence of an acid followed by basification with sodium hydroxide to get the 4-hydroxy-3, 5- diisopropylbenzoic acid.
- the alkylating agent can be selected from diisopropyl ether, isopropyl alcohol, isopropyl halide, preferably diisopropyl ether.
- Acid is selected from mineral acid, preferably sulfuric acid, perchloric acid.
- the alkylation of p-hydroxybenzoic acid in presence of an acid controls further alkylation and excessive formation of isomeric byproducts like 2, 4-diisopropyl phenol and 2, 4, 6-trisisopropyl phenol, which are difficult to remove.
- 4-hydroxy-3, 5-diisopropyl benzoic acid is subjected to decarboxylation in presence of high boiling solvents and alkali metal hydroxide as a catalyst in an inert atmosphere to yield 2, 6-diisopropyl phenol.
- the 2, 6-diisopropyl phenol thus formed is further extracted by using hydrocarbon solvents such as toluene and then washing the organic layer with aqueous sodium bicarbonate and followed by water. After removal of solvent the residue is distilled off under high vacuum to give pure 2, 6-diisopropyl phenol having purity of 99.9%.
- the high boiling solvents used are preferably ethylene glycol, dimethylformamide or dimethylacetamide.
- the catalyst used during the decarboxylation is selected from alkali metal hydroxide such as sodium or potassium hydroxide.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A method for obtaining high purity 2, 6-diisopropylphenol comprises alkylating 4- hydroxybenzoic acid in presence of an acid followed by basification and decarboxylating 4- hydroxy-3, 5-diisopropylbenzoic acid in presence of high boiling solvents and a catalyst at high temperature.
Description
SPECIFICATION
TITLE OF THE INVENTION
Phenol C-alkylation process. FIELD OF THE INVENTION The invention relates to the process for producing ortho-isopropylated phenol. CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority from the provisional patent application number 3038/CHE/2011 filed on 05.09.2011. BACKGROUND OF THE INVENTION
A typical example of ortho-isopropylated phenol is 2, 6-diisopropyl phenol, commonly known as Propofol, use as an anaesthetic for parenteral administration and such a use is become common in surgery. Since Propofol is administered by parenteral route, its purity degree must be very high. Several patents/patent applications have been filed for the preparation and purification of Propofol such as US2831898, US3367981, US3766276, US4103096, US5175376, US5414156, US4208537, US4275248, US4447657, US4538009 and US4559465.
US2831898 discloses a process for producing 2, 6-diisopropyl phenol from propylene gas and phenol by Friedel-Crafts reaction at high pressure, high temperature and under nitrogen atmosphere with aluminum phenoxide, as a catalyst, prepared from alumina and phenol. But desired 2,6-diisopropyl phenol was obtained with very low yield along with other isomers and phenol derivatives such as 2,4-, 2,5-diisopropyl phenol, 2,4, 6- trisisopropyl phenol, 1- isopropoxy-2,4-diisopropyl benzene etc. The compounds formed in the reaction separated by fractional distillation, but this is very difficult due to small differences in the boiling points of the compound to be separated. Thus, after fractional distillation the products still contains high level of impurities.
US3367981 discloses the preparation method of a mixture of 2-isopropyl phenol and 2, 6- diisopropyl phenol by heating of a mixture of phenol and propylene gas to 314°C at nitrogen atmosphere in air tight vessel on a transitional alumina, as a catalyst, prepared by heating of an aluminum oxide hydrate and further adding a propylene gas at 310-312°C after reducing a resultant pressure. The yield of 2, 6-diidsopropyl phenol is low and the yield of 2-isopropyl phenol is high.
US4447657 discloses the process for producing 2, 6- diisopropyl phenol by contacting isopropyl (2-isopropyl phenyl) ether with fluoride alumina under nitrogen pressure at 150°C and a 200 psi. This method uses the thermal rearrangement of alkyl phenyl ether. Drawback of this process is that 2, 6-diisopropyl phenol has low yield and 2-isopropyl phenol and 2, 4, 6-trisisopropyl phenol which are by-products have high yield.
These processes suffer serious drawbacks since yield of 2, 6-diisopropyl phenol is quite low and require high pressure, high temperature and product need to have complicated separation procedure because reaction product is a mixture of positional isomers. US5175376 discloses a method for the purification of 2, 6-diisopropyl phenol by fractional crystallization at very low temperature from -25° to +18 °C. Such a procedure is not well suited for use in a large scale commercial preparation.
US5705039 discloses a process for the purification of impure 2,6-diisopropylphenol which comprises: a) subjecting the impure 2,6-diisopropylphenol to a first continuous distillation in a single distillation column in an inert environment to produce (i) a first overhead distillate of impurities boiling below the boiling point of 2,6-diisopropylphenol at the prevailing pressure and
(ii) first column bottoms enriched in 2,6-diisopropylphenol; b) collecting, cooling and storing the first column bottoms while continuously maintaining them in an inert environment; c) discontinuing the first continuous distillation; d) subjecting said first column bottoms to a second continuous distillation in an inert environment in the same single distillation column to produce a second overhead distillate composed of purified 2,6-diisopropylphenol. This process is not, economically viable.
US5591311 discloses the process of purification of an impure 2, 6-diisopropylphenol mixture washing said mixture with aqueous alkali metal hydroxide solution and/or aqueous alkaline earth metal hydroxide solution in an inert atmosphere and separating the aqueous and organic phases, washing the resulting organic phase with water, and then subjecting the water- washed organic phase to distillation in an inert environment to recover purified 2, 6-diisopropylphenol.
US5589598 describes a process for the purification of 2, 6-diisopropyl phenol by transformation of crude 2, 6-diisopropyl phenol into its ester with a carboxylic or sulphonic acid, followed by crystallization and hydrolysis.
Due to above drawbacks in the preparation of 2, 6-diisopropyl phenol, the object of the present invention is to provide an improved process for producing the 2, 6-diisopropyl phenol having high purity at low temperature and low pressure without producing by-products and therefore no requirement of the complicated separation procedure.
SUMMARY OF THE INVENTION
An improved process for producing the 2, 6-diisopropyl phenol having high purity comprising of the alkylation of 4-hydroxybenzoic acid in presence of an acid to get the 4-hydroxy-3, 5- diisopropylbenzoic acid followed by decarboxylation in presence of high boiling solvents and a catalyst. The 2, 6-diisopropyl phenol, commonly known as Propofol, is used as an anaesthetic for parenteral administration in surgery. .
The object of the present invention is to provide a new, economical and highly effective process for producing high purity 2, 6-diisopropyl phenol.
Another object of the present invention is to provide a process for the synthesis of 2, 6- diisopropyl phenol, the process comprising the reaction of 4-hydroxybenzoic acid with alkylating agent in presence of an acid to get 4-hydroxy-3, 5-diisopropylbenzoic acid followed by decarboxylation in presence of high boiling solvents and a catalyst to get the high purity 2, 6- diisopropylphenol.
Yet another object of the invention is to provide a process to get the 2, 6-diisopropyl phenol with the purity greater than 99.9%.
DESCRIPTION OF THE INVENTION
In accordance with the present invention 2, 6-diisopropyl phenol is obtained by the alkylation of 4-hydroxybenzoic acid in presence of an acid to get the 4-hydroxy-3, 5-diisopropylbenzoic acid followed by decarboxylation in presence of high boiling solvents and a catalyst. The process of the invention is depicted in following scheme-
4 - Hydroxybenzoic acid (II) 4 - Hydroxy - 3,5 - diisopropylbenzoic acid (III) 2,6 - diisopropyl phenol (I) The 4-hydroxybenzoic acid which is the starting material for the present process is commercially available.
In an embodiment, the process of the present invention comprises Friedel Crafts' s alkylation of 4-hydroxybenzoic acid in presence of an acid followed by basification with sodium hydroxide to get the 4-hydroxy-3, 5- diisopropylbenzoic acid. The alkylating agent can be selected from diisopropyl ether, isopropyl alcohol, isopropyl halide, preferably diisopropyl ether. Acid is selected from mineral acid, preferably sulfuric acid, perchloric acid.
The alkylation of p-hydroxybenzoic acid in presence of an acid controls further alkylation and excessive formation of isomeric byproducts like 2, 4-diisopropyl phenol and 2, 4, 6-trisisopropyl phenol, which are difficult to remove.
In another embodiment, 4-hydroxy-3, 5-diisopropyl benzoic acid is subjected to decarboxylation in presence of high boiling solvents and alkali metal hydroxide as a catalyst in an inert atmosphere to yield 2, 6-diisopropyl phenol. The 2, 6-diisopropyl phenol thus formed is further extracted by using hydrocarbon solvents such as toluene and then washing the organic layer with aqueous sodium bicarbonate and followed by water. After removal of solvent the residue is distilled off under high vacuum to give pure 2, 6-diisopropyl phenol having purity of 99.9%.
The high boiling solvents used are preferably ethylene glycol, dimethylformamide or dimethylacetamide.
The catalyst used during the decarboxylation is selected from alkali metal hydroxide such as sodium or potassium hydroxide.
The invention is further illustrated with following non-limiting examples:
Example: 1 Preparation of 4-hydroxy 3, 5-diisopropylbenzoic acid
4-hydroxy benzoic acid (100 g) was added portion wise to a sulfuric acid (360 ml, 9.37mmol) at 10-15°C. Diisopropyl ether was added slowly to the above mixture at 10-15°C. Mixture was stirred at this temperature for 10 minutes. Temperature was raised up to 60-65°C and stirred at same temperature for 2 - 4 hours. After completion of the reaction, mixture was cooled to 45°C and solution of sodium hydroxide (590g/2000ml water) was added to the reaction mixture. The mixture was cooled to room temperature and kept under stirring for 15 minutes. Toluene (2x400 ml) was added to above reaction mixture. The layers were separated. Aqueous phase pH was adjusted to 1-2 with HC1 at room temperature. The resulting precipitate was stirred for 60 minutes, filtered off the precipitate and washed with hot water (2X250ml). The solid was dried under air oven at 70-75°C up to constant weight (120g).
Example: 2- Purification of crude 3, 5-diisopropyl-4-hydroxybenzoic acid
3, 5-diisopropyl-4-hydroxybenzoic acid (120 g) was dissolved in methanol (350 ml). Solution was heated to 60-65°C. Activated carbon (5g) was added to the above solution at 60-65°C and stirred for 30 minutes. Reaction mixture was filtered off in hot condition and washed with hot
methanol (50 ml). Filtrate was cooled to 10-15 C and water (1000ml) was added. The resulting precipitate was filtered off and washed with water (2X200ml). The solid was dried under air oven at 70-75 °C up to constant weight to get pure 3, 5-diisopropyl-4-hydroxybenzoic acid (102 g)- Example: 3- Preparation of 2, 6-diisopropyI phenol
Sodium hydroxide flakes (41.5 g; 2.3 mmol) was added to 4-hydroxy-3, 5-diisopropyl benzoic acid (100 g) and ethylene glycol (150 ml). The resulting mixture was heated to the temperature up to 140-145°C and stirred for 4-7 hours. Reaction mass was cooled to room temperature. Water (500 ml) was added at room temperature. Reaction mass was stirred for 30 minutes at room temperature. pH of the reaction mixture was adjusted 1-2 with con HCl at room temperature and stirred for 30 minutes. Layers were separated and Toluene (400ml) was added in the aqueous phase. Organic phase was washed with 5% sodium bicarbonate solution (2x50 ml) and water (200 ml). Organic layer was separated and distilled off toluene under vacuum (650-700 mm of Hg) at 70-75°C for 30 minutes. Compound was degassed under vacuum (650-700 mm of Hg) for 30 minutes at 70-75 °C. Crude residue was heated upto 108°C and collected different fractions (Fl ; F2; F3) at different temperature (6- 108 °C; 108 °C; 100- 108 °C) respectively and combine all fraction to obtained pure 2, 6-diisopropyl phenol (53 g).
Claims
1. A process for the preparation of 2,6-diisopropyl phenol compound of formula 1
Formula - II with alkylating agent in the presence of an acid to give a compound having the formula-Ill
Formula - 1 b) combining formula-Ill with a catalyst in presence of high boiling solvent to compound of formula-I.
2. The alkylating agent as claimed in step (a) of the process according to claim 1, is selected from the group consisting of diisopropyl ether or isopropyl alcohol or isopropyl halide, but preferably diisopropyl ether.
3. The acid used in step (a) of claim 1 is selected from mineral acid such as sulfuric, or perchloric acid, but preferably sulfuric acid.
4. The high boiling solvent used in step (b) of claim 1 is selected from the group consisting of ethylene glycol or dimethylformamide or dimethylacetamide.
5. The catalyst used in step (b) of claim 1 is selected from alkali metal hydroxide such as sodium or potassium hydroxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IN3038CH2011 | 2011-09-05 | ||
| IN3038/CHE/2011 | 2011-09-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2013035103A1 true WO2013035103A1 (en) | 2013-03-14 |
Family
ID=47831614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IN2011/000689 WO2013035103A1 (en) | 2011-09-05 | 2011-10-03 | Phenol c-alkylation process |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2013035103A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020114925A1 (en) * | 2018-12-07 | 2020-06-11 | Covestro Deutschland Ag | Method for producing a hydroxy compound by decarboxylation in the presence of a bronsted base |
| CN113227030A (en) * | 2018-12-07 | 2021-08-06 | 科思创知识产权两合公司 | Method for producing hydroxy compounds by decarboxylation |
| CN113382978A (en) * | 2018-12-07 | 2021-09-10 | 科思创知识产权两合公司 | Method for producing hydroxy compounds by decarboxylation in the absence of a catalyst |
| WO2021191832A1 (en) | 2020-03-26 | 2021-09-30 | Fresenius Kabi Oncology Ltd. | Process for the preparation of propofol |
| WO2023111488A1 (en) | 2021-12-17 | 2023-06-22 | Pcas | Process for producing propofol |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU443019A1 (en) * | 1973-01-05 | 1974-09-15 | Предприятие П/Я Г-4740 | The method of obtaining 2,6-diisopropylphenol |
| US5705039A (en) * | 1995-10-13 | 1998-01-06 | Albemarle Corporation | Process for purifying a 2,6-dialkylphenol |
-
2011
- 2011-10-03 WO PCT/IN2011/000689 patent/WO2013035103A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU443019A1 (en) * | 1973-01-05 | 1974-09-15 | Предприятие П/Я Г-4740 | The method of obtaining 2,6-diisopropylphenol |
| US5705039A (en) * | 1995-10-13 | 1998-01-06 | Albemarle Corporation | Process for purifying a 2,6-dialkylphenol |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020114925A1 (en) * | 2018-12-07 | 2020-06-11 | Covestro Deutschland Ag | Method for producing a hydroxy compound by decarboxylation in the presence of a bronsted base |
| CN113227029A (en) * | 2018-12-07 | 2021-08-06 | 科思创知识产权两合公司 | Method for producing hydroxy compounds by decarboxylation in the presence of Bronsted bases |
| CN113227030A (en) * | 2018-12-07 | 2021-08-06 | 科思创知识产权两合公司 | Method for producing hydroxy compounds by decarboxylation |
| CN113382978A (en) * | 2018-12-07 | 2021-09-10 | 科思创知识产权两合公司 | Method for producing hydroxy compounds by decarboxylation in the absence of a catalyst |
| CN113227030B (en) * | 2018-12-07 | 2023-09-12 | 科思创知识产权两合公司 | Process for preparing hydroxy compounds by decarboxylation |
| WO2021191832A1 (en) | 2020-03-26 | 2021-09-30 | Fresenius Kabi Oncology Ltd. | Process for the preparation of propofol |
| WO2023111488A1 (en) | 2021-12-17 | 2023-06-22 | Pcas | Process for producing propofol |
| FR3130797A1 (en) | 2021-12-17 | 2023-06-23 | Pcas | METHOD FOR THE PREPARATION OF PROPOFOL |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2013035103A1 (en) | Phenol c-alkylation process | |
| EP2516369B1 (en) | Process for preparing extra pure 2, 6-diisopropyl phenol | |
| JP3701974B2 (en) | Method for purifying 2,6-diisopropylphenol | |
| TW200405891A (en) | Method for preparation of hydroxybenzoic acids | |
| WO2011113228A1 (en) | A process for preparing guaiacol glycidyl | |
| JP7141303B2 (en) | Method for producing 5,5'-methylenedisalicylic acid | |
| JPH0674227B2 (en) | Process for producing p, p'-biphenol | |
| CN106565424B (en) | Preparation method of high-purity propofol | |
| CN116283504B (en) | Synthesis method of 2, 4-dicumyl phenol | |
| US7714173B2 (en) | Method for purifying terephthalaldehyde | |
| US3346649A (en) | Selective partial dealkylation of tertiary alkylated phenols | |
| KR850001156B1 (en) | Process for the preparation of 2-methoxy-3,6-dichlorobenzoic | |
| JPS62242644A (en) | Method for oxidizing alkylphenol or such | |
| US8987525B2 (en) | Process for the preparation of polyhydroxystilbene compounds by deprotection of the corresponding ethers | |
| JP3991715B2 (en) | Method for producing alkylidene bisphenols | |
| JP2697054B2 (en) | Method for producing p-hydroxybenzaldehyde | |
| JP2697056B2 (en) | Method for producing p-hydroxybenzaldehyde | |
| JP2767764B2 (en) | Production method of bisphenols | |
| JP6503220B2 (en) | Purification method of 4-hydroxybenzoic acid long chain ester | |
| US2654774A (en) | Method of making 4-tertiary-butylphenyl salicylate | |
| JP2016210699A (en) | Manufacturing method of 4-hydroxy benzoic acid long chain ester | |
| WO2020179769A1 (en) | Production method for 4-hydroxy-2-methyl benzoate | |
| JPH0853390A (en) | Production of bis(hydroxyaryl)pentanoic acids | |
| KR101521607B1 (en) | Process of isolating methyl-4-formylbenzoate and dimethylterephtalate with high yield | |
| US5107031A (en) | Proces to recover 4-phenoxybiphenyl |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 11872026 Country of ref document: EP Kind code of ref document: A1 |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| 122 | Ep: pct application non-entry in european phase |
Ref document number: 11872026 Country of ref document: EP Kind code of ref document: A1 |