CA1173859A - Process for the preparation of phenol ethers - Google Patents
Process for the preparation of phenol ethersInfo
- Publication number
- CA1173859A CA1173859A CA000387190A CA387190A CA1173859A CA 1173859 A CA1173859 A CA 1173859A CA 000387190 A CA000387190 A CA 000387190A CA 387190 A CA387190 A CA 387190A CA 1173859 A CA1173859 A CA 1173859A
- Authority
- CA
- Canada
- Prior art keywords
- phenol
- reaction
- process according
- mixture
- alcohol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 21
- 230000008569 process Effects 0.000 title claims abstract description 21
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- 150000008379 phenol ethers Chemical class 0.000 title abstract description 9
- 239000003054 catalyst Substances 0.000 claims abstract description 20
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000003930 superacid Substances 0.000 claims abstract description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 11
- -1 aliphatic alcohols Chemical class 0.000 claims abstract description 8
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 33
- 239000000203 mixture Substances 0.000 claims description 28
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 claims description 24
- 238000006243 chemical reaction Methods 0.000 claims description 17
- 239000002253 acid Substances 0.000 claims description 14
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 claims description 8
- 150000007513 acids Chemical class 0.000 claims description 5
- 239000000376 reactant Substances 0.000 claims description 4
- 239000011347 resin Substances 0.000 claims description 4
- 229920005989 resin Polymers 0.000 claims description 4
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 claims description 4
- DNIAPMSPPWPWGF-GSVOUGTGSA-N (R)-(-)-Propylene glycol Chemical compound C[C@@H](O)CO DNIAPMSPPWPWGF-GSVOUGTGSA-N 0.000 claims description 3
- 239000003456 ion exchange resin Substances 0.000 claims description 3
- 229920003303 ion-exchange polymer Polymers 0.000 claims description 3
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims description 2
- QTWJRLJHJPIABL-UHFFFAOYSA-N 2-methylphenol;3-methylphenol;4-methylphenol Chemical compound CC1=CC=C(O)C=C1.CC1=CC=CC(O)=C1.CC1=CC=CC=C1O QTWJRLJHJPIABL-UHFFFAOYSA-N 0.000 claims description 2
- 150000005840 aryl radicals Chemical group 0.000 claims description 2
- 229930003836 cresol Natural products 0.000 claims description 2
- 239000002904 solvent Substances 0.000 claims description 2
- KJCVRFUGPWSIIH-UHFFFAOYSA-N 1-naphthol Chemical compound C1=CC=C2C(O)=CC=CC2=C1 KJCVRFUGPWSIIH-UHFFFAOYSA-N 0.000 claims 1
- 125000002256 xylenyl group Chemical class C1(C(C=CC=C1)C)(C)* 0.000 claims 1
- 150000008442 polyphenolic compounds Polymers 0.000 abstract description 2
- 235000013824 polyphenols Nutrition 0.000 abstract description 2
- LHGVFZTZFXWLCP-UHFFFAOYSA-N guaiacol Chemical compound COC1=CC=CC=C1O LHGVFZTZFXWLCP-UHFFFAOYSA-N 0.000 description 14
- 229920000557 Nafion® Polymers 0.000 description 10
- 239000000047 product Substances 0.000 description 8
- 239000011541 reaction mixture Substances 0.000 description 8
- 229960001867 guaiacol Drugs 0.000 description 7
- ABDKAPXRBAPSQN-UHFFFAOYSA-N veratrole Chemical compound COC1=CC=CC=C1OC ABDKAPXRBAPSQN-UHFFFAOYSA-N 0.000 description 6
- 150000002989 phenols Chemical class 0.000 description 5
- RDOXTESZEPMUJZ-UHFFFAOYSA-N anisole Chemical compound COC1=CC=CC=C1 RDOXTESZEPMUJZ-UHFFFAOYSA-N 0.000 description 4
- 238000006266 etherification reaction Methods 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- MYRTYDVEIRVNKP-UHFFFAOYSA-N 1,2-Divinylbenzene Chemical compound C=CC1=CC=CC=C1C=C MYRTYDVEIRVNKP-UHFFFAOYSA-N 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- UZKWTJUDCOPSNM-UHFFFAOYSA-N methoxybenzene Substances CCCCOC=C UZKWTJUDCOPSNM-UHFFFAOYSA-N 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- NWVVVBRKAWDGAB-UHFFFAOYSA-N p-methoxyphenol Chemical compound COC1=CC=C(O)C=C1 NWVVVBRKAWDGAB-UHFFFAOYSA-N 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- NQMUGNMMFTYOHK-UHFFFAOYSA-N 1-methoxynaphthalene Chemical class C1=CC=C2C(OC)=CC=CC2=C1 NQMUGNMMFTYOHK-UHFFFAOYSA-N 0.000 description 1
- BBGJFAYGMNGEIW-UHFFFAOYSA-N 2,6-ditert-butyl-4-[[4-[(3,5-ditert-butyl-4-hydroxyphenyl)methyl]piperazin-1-yl]methyl]phenol Chemical compound CC(C)(C)C1=C(O)C(C(C)(C)C)=CC(CN2CCN(CC=3C=C(C(O)=C(C=3)C(C)(C)C)C(C)(C)C)CC2)=C1 BBGJFAYGMNGEIW-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000002841 Lewis acid Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 229940100198 alkylating agent Drugs 0.000 description 1
- 239000002168 alkylating agent Substances 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 244000309464 bull Species 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 229940077445 dimethyl ether Drugs 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- LRMHFDNWKCSEQU-UHFFFAOYSA-N ethoxyethane;phenol Chemical compound CCOCC.OC1=CC=CC=C1 LRMHFDNWKCSEQU-UHFFFAOYSA-N 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- UQSQSQZYBQSBJZ-UHFFFAOYSA-N fluorosulfonic acid Chemical compound OS(F)(=O)=O UQSQSQZYBQSBJZ-UHFFFAOYSA-N 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- ZSIAUFGUXNUGDI-UHFFFAOYSA-N hexan-1-ol Chemical compound CCCCCCO ZSIAUFGUXNUGDI-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 150000007517 lewis acids Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000011987 methylation Effects 0.000 description 1
- 238000007069 methylation reaction Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- ITMCEJHCFYSIIV-UHFFFAOYSA-N triflic acid Chemical compound OS(=O)(=O)C(F)(F)F ITMCEJHCFYSIIV-UHFFFAOYSA-N 0.000 description 1
- 150000003739 xylenols Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/09—Preparation of ethers by dehydration of compounds containing hydroxy groups
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for the preparation of phenol ethers from mono- or poly-phenols and aliphatic alcohols with high selec-tivity using catalysts containing "superacids", at temperatures between 110° and 170°C, with phenol:alcohol ratios between 2:1 and 6:1.
A process for the preparation of phenol ethers from mono- or poly-phenols and aliphatic alcohols with high selec-tivity using catalysts containing "superacids", at temperatures between 110° and 170°C, with phenol:alcohol ratios between 2:1 and 6:1.
Description
~a'7~5~'~
The present invention relates to a process for the preparation of phenol ethers from phenols and aliphatic alco-hols.
The importance of phenol ethers in the Chemical indus-try, in particular in pharmaceuticals, dye-stuffs, antioxidant agents, cosmetics is well known. Products such as anisole, guaiacol, hydroquinone monomethyl ether, guetol, methyl-naphthyl ethers are widely used and find a large market.
Hitherto many processes have been suggested and used for the preparation of phenol ethers. The processes most used for the preparation of phenol ethers involve the reaction of an alkyl sulphate or chloride with an alkaline phenate.
The main disadvantages of these processes on industrial scale are: 1. the alkylating agents are rather toxic and, in some cases, volatile with the consequent problems of environmental hygiene and pollution; and 2. stoichiometrical amounts of mineral salts (alkali sulphates and chlorides) are formed in the reaction, causing great disposal problems.
To overcome these disadvantages, several processes have been developed for the preparation of phenol ethers direct-ly from phenols and alcohols according to the equation:
Ar - OH + R - OH Ar - OR + H2O (I) The characteristics of the catalyst play an essential role in this reaction. Hitherto two kinds of catalysts have been used: (a) metal salts and oxides; (b) acid ion exchange resins.
Type ~a) catalysts (see Japan Patents Nos. 8099-129 and 71-11494) do not give very satisfactory results, because they are not suEficiently selecti~e, therefore forming large amounts of side products, particularly products having alkyl ~roups on the benzene ring. Type (b) catalysts (see Nippon ~aishi 8, 1513, (1974); USSR Patent 197613; and ~rench Patent ' ~
~ .
The present invention relates to a process for the preparation of phenol ethers from phenols and aliphatic alco-hols.
The importance of phenol ethers in the Chemical indus-try, in particular in pharmaceuticals, dye-stuffs, antioxidant agents, cosmetics is well known. Products such as anisole, guaiacol, hydroquinone monomethyl ether, guetol, methyl-naphthyl ethers are widely used and find a large market.
Hitherto many processes have been suggested and used for the preparation of phenol ethers. The processes most used for the preparation of phenol ethers involve the reaction of an alkyl sulphate or chloride with an alkaline phenate.
The main disadvantages of these processes on industrial scale are: 1. the alkylating agents are rather toxic and, in some cases, volatile with the consequent problems of environmental hygiene and pollution; and 2. stoichiometrical amounts of mineral salts (alkali sulphates and chlorides) are formed in the reaction, causing great disposal problems.
To overcome these disadvantages, several processes have been developed for the preparation of phenol ethers direct-ly from phenols and alcohols according to the equation:
Ar - OH + R - OH Ar - OR + H2O (I) The characteristics of the catalyst play an essential role in this reaction. Hitherto two kinds of catalysts have been used: (a) metal salts and oxides; (b) acid ion exchange resins.
Type ~a) catalysts (see Japan Patents Nos. 8099-129 and 71-11494) do not give very satisfactory results, because they are not suEficiently selecti~e, therefore forming large amounts of side products, particularly products having alkyl ~roups on the benzene ring. Type (b) catalysts (see Nippon ~aishi 8, 1513, (1974); USSR Patent 197613; and ~rench Patent ' ~
~ .
2.373.506) allow one to obtain good selectivities only at very low reaction rates (20-60 hours). If one tries to increase the reaction rate by means of a raise in temperature, an oppo-site effect is obtained, because the reaction rate is further reduced and also the selectivity is greatly lowered. Moreover the catalyst deteriorates and it cannot be recycled.
The present invention provides a process for the pre-paration of phenol ethers by the direct reaction of phenols with aliphatic alcohols according to the e~uation;
Ar(OH)n + ROH - ArOR(OH) 1 + H2O
in which Ar is an aryl radical, R is a Cl-C6 aliphatic radical, and n is 1 or 2, using "superacids" as catalysts. This pro-cess overcomes all the above-mentioned disadvantages and allows for the production of phenol ethers at high reaction rates and selectivities of nearly 100%, with good conversions of the phenol and nearly theoretical yields of the product.
The "superacids" are compounds or catalytic systems generally composed of particular acids or mixtures of Lewis acids with protic acids. Their preparation and use are rela-tively recent (see Bull. Soc. Chim. de France 1976, n 11-12;
1979, n. 5-6). All the superacids are characterized by a Ho value lower than that of sulphuric acid, which is about -12.
The superacids including fluorinated sulphonic acids such as trifluoromethansulphonic acid and its higher homolo-gous acids, and perfluorosulphonic resins such as those pro-duced by Du Pont under the trade-mark Nafion are particularly useful.
The process of the present invention may be carried out in the heterogeneous phase using a solid insoluble catalyst and mixing phenol and alcohol according to ratios between 2:1 and 6:1, at temperatures between 110 and 170, at atmospheric pressure or under pressure, according to the boiling point of 7~
the reaction mixture.
The amount of the catalyst in the reaction mixture is between 1 and 30~ (by weight) based on the weight of reac tants.
Moreover it is possible to work in homogeneous phase, using a soluble superacid and a solvent for the two reactants, which is inert under the reaction conditions, such as for exam-ple a hydrocarbon, a halogenated hydrocarbon, or dioxane. The reaction conditions are the same as in the heterogeneous phase.
The process can be used for the etherification of any commercial phenol such as, for example: phenol, cresol, xylen-ols, pyrocatechol, hydroquinone, resorcinol and naphtols. It is particularly useful that the process, in the case of poly-phenols, gives the mono-ether with high selectivity. As the aliphatic alcohol any Cl~C6 alcohol can be used. Nevertheless the use of methanol or ethanol is particularly interesting, because the methyl- and ethyl-ethers are very important.
The excess of unreacted phenol is separated from the phenol-ether and recycled. Any suitable separation process can be used according to the products involved. Usually the separation is accomplished by distillation.
If the reaction is carried out in heterogeneous phase, the catalyst can be separated from the reaction mixture by decantation, filtration or centrifugation, and utilized in subsequent cycles, as it does not lose its activity under the conditions of the reaction.
Moreover it has been found that the "superacids"
catalysts, used in the process according to the present inven-tion, can be used also in mixture with conventional catalysts for the direct etherification, composed of acid ion-e~change resins. In this case the reaction rate increases with the superacid percentage and therefore reaction times can be ~73~
obtained which are 2-4 times shorter than obtained with con-ventional catalysts. The amounts of the two catalysts used in the reaction are between 1 and 30~ (by weight) based on the weight of the reaction mixture.
The advantage of the use of catalysts mixture lies in the great reduction of the reaction times compared with con-ventional methods, using smaller amounts of superacid, and therefore the utilization of these mixtures is preferred in the case of a superacid of relatively high cost.
The possibility of using "superacids" and in particu-lar resins of the Nafion (a trademark) type, as catalysts for the direct etherification (with nearly 100% selectivity) of phenols with aliphatic alcohols, was quite unexpected, since it is well known (J. Org. Chem. vol 43, N.16, 1978; J. of Catalysis 61, 96-102, 1980) that catalysts of the Nafion (a trademark) type catalyze the methylation of the ring and the formation of the dimethyl-ether in a mixture of phenols and methanol.
Nothing suggested that the process could follow a quite different course, so as to achieve an almost complete selectivity for the mono-etherification process, under different reaction conditions, in particular as regards the ratios be-tween the reactants and the temperature.
The present invention will be further illustrated, by way of the following Examples.
EXA~PLE 1 125 g ~1.135 moles) of pyrocatechol, 14.5 g (0.454 moles) of methanol and 30.6 g (0.03063 equiv.) of perfluorosul-phonic acid (Nafion 501 a trademark of Du Pont) are placed in a flask equipped with a stirrer, thermometer and reflux conden-ser. The mixture is heated at 120C for 5 hours. After this reaction time, the composition of the mixtures is as follows:
5~3 Unconverted pyrocatechol 87%
Guaiacol 12.8%
Compounds with methyl groups o lQ
on the ring Veratrole 0.1%
The yield of guaiacol on the converted pyrocatechol can be considered almost quantitative.
Operating exactly as previously described, but using as catalyst an ion exchange resin composed of polystyrenesul-phonic acid cross-linked with divinylbenzene (supplied under the trademark Amberlist 15), in an amount corresponding to 0 ~ 03063 acid equiv., a reaction mixture is obtained after 5 hours, having the following composition: _ Unreacted pyrocatechol98.8%
Guaiacol 1.0%
Compounds with methyl groups o 1%
on the ring Veratrole 0.1%
250 g of pyrocatechol (2.27 moles), 36 ~ 3 g of methanol (1.135 moles) and 61n 2 g of Nafion 501 (a trademark) corres-ponding to 0. 0612 acid equiv. are placed in the same flask of Example 1. The mixture is heated at 150 - 155 C for 5 hours.
After this reaction time the composition of the reaction mix-ture is as follows:
Unreacted pyrocatechol80~o Guaiacol 18. 5%
Methylated compounds1~0~o Veratrole o. 5%
107 g of phenol (1.135 moles), 14.5 g of methanol (0.454 moles) and 30.6 g of Nafion 501 (a trademark) (0.03063 equiv.) are placed in the same flask of Example 1. The mixture is heated at 120C for 5 hours. After this time the composi-tion of the reaction mixture is as follows:
Unreacted phenol 85%
Anisole 14.9%
Alkylated products 0.1%
250 g of pyrocatechol (2.27 moles), 3.63 g of methan-ol (0.1135 moles) and 61.2 g of perfluorosulphonic acid (0.0612 acid equiv.) are placed in the same flask of Example 1. The _ mixture is heated at 150-155C for 1 hour and then again 3.63 g of methanol are added. The mixture is further heated at 150-155C for 1 hour and afterwards 3.63 g of methanol are again added, continuing to heat at 150-155C. After 3 hours the mix-ture has the following composition:
Unreacted pyrocatechol 88.6 Guaiacol 11.4 EXA~IPLE 5 125 g of hydroquinone (1.135 moles), 14.5 g of methanol (0.454 moles) and 30.6 g (0.03063 acid equiv.) of Nafion 501 (a trademark of Du Pont), are placed in the same flask of Example 1. The mixture is heated at 120C for 5 hours. After this time the reaction mixture has the following com~osition:
Unreacted hydroquinone 90.5%
Hydroquinone monomethylether 9.4Q
Pxoducts with ring a'kylation 0.1 j ~ .1 '7~
125 g o~ pyrocatechol (1.135 moles), 21 g of ethanol (0.455 moles) and 30.6 g (0.03063 equiv.) of Nafion 501 (a trademark) are placed in the same flask of Example 1. The mixture is heated at 120C for 5 hours. After this time the composition of the mixture is as follows:
Unconverted pyrocatechol 85%
Guetol 14.5%
Other products 0.5%
162 g of ~-naphtol (1.135 moles), 14.5 g of methanol (0.454 moles) and 30.6 g (0.03063 equiv.) of Nafion 501 (a trademark) are placed in the same flask of Example 1. The mixture is heated at 125C for 5 hours. After this time the composition of the mixture resulted to be as follows:
Unconverted ~-naphtol 86%
~-naphtol monomethylether 13.7%
Other products 0.3%
125 g of pyrocatechol (1.135 moles), 14.5 g of methanol (0.454 moles) 0.01 equivalents of Nafion 501 (a trade-mark) and 0.02 equiv. of Amberlist 15 (a trademark) are placed in the same flask of Example 1. The mixture is heated at 125C for 5 hours. After this time the mixture has the follow-ing composition:
Unreacted pyrocatechol 89%
Guaiacol 10.9 Other products 0.1
The present invention provides a process for the pre-paration of phenol ethers by the direct reaction of phenols with aliphatic alcohols according to the e~uation;
Ar(OH)n + ROH - ArOR(OH) 1 + H2O
in which Ar is an aryl radical, R is a Cl-C6 aliphatic radical, and n is 1 or 2, using "superacids" as catalysts. This pro-cess overcomes all the above-mentioned disadvantages and allows for the production of phenol ethers at high reaction rates and selectivities of nearly 100%, with good conversions of the phenol and nearly theoretical yields of the product.
The "superacids" are compounds or catalytic systems generally composed of particular acids or mixtures of Lewis acids with protic acids. Their preparation and use are rela-tively recent (see Bull. Soc. Chim. de France 1976, n 11-12;
1979, n. 5-6). All the superacids are characterized by a Ho value lower than that of sulphuric acid, which is about -12.
The superacids including fluorinated sulphonic acids such as trifluoromethansulphonic acid and its higher homolo-gous acids, and perfluorosulphonic resins such as those pro-duced by Du Pont under the trade-mark Nafion are particularly useful.
The process of the present invention may be carried out in the heterogeneous phase using a solid insoluble catalyst and mixing phenol and alcohol according to ratios between 2:1 and 6:1, at temperatures between 110 and 170, at atmospheric pressure or under pressure, according to the boiling point of 7~
the reaction mixture.
The amount of the catalyst in the reaction mixture is between 1 and 30~ (by weight) based on the weight of reac tants.
Moreover it is possible to work in homogeneous phase, using a soluble superacid and a solvent for the two reactants, which is inert under the reaction conditions, such as for exam-ple a hydrocarbon, a halogenated hydrocarbon, or dioxane. The reaction conditions are the same as in the heterogeneous phase.
The process can be used for the etherification of any commercial phenol such as, for example: phenol, cresol, xylen-ols, pyrocatechol, hydroquinone, resorcinol and naphtols. It is particularly useful that the process, in the case of poly-phenols, gives the mono-ether with high selectivity. As the aliphatic alcohol any Cl~C6 alcohol can be used. Nevertheless the use of methanol or ethanol is particularly interesting, because the methyl- and ethyl-ethers are very important.
The excess of unreacted phenol is separated from the phenol-ether and recycled. Any suitable separation process can be used according to the products involved. Usually the separation is accomplished by distillation.
If the reaction is carried out in heterogeneous phase, the catalyst can be separated from the reaction mixture by decantation, filtration or centrifugation, and utilized in subsequent cycles, as it does not lose its activity under the conditions of the reaction.
Moreover it has been found that the "superacids"
catalysts, used in the process according to the present inven-tion, can be used also in mixture with conventional catalysts for the direct etherification, composed of acid ion-e~change resins. In this case the reaction rate increases with the superacid percentage and therefore reaction times can be ~73~
obtained which are 2-4 times shorter than obtained with con-ventional catalysts. The amounts of the two catalysts used in the reaction are between 1 and 30~ (by weight) based on the weight of the reaction mixture.
The advantage of the use of catalysts mixture lies in the great reduction of the reaction times compared with con-ventional methods, using smaller amounts of superacid, and therefore the utilization of these mixtures is preferred in the case of a superacid of relatively high cost.
The possibility of using "superacids" and in particu-lar resins of the Nafion (a trademark) type, as catalysts for the direct etherification (with nearly 100% selectivity) of phenols with aliphatic alcohols, was quite unexpected, since it is well known (J. Org. Chem. vol 43, N.16, 1978; J. of Catalysis 61, 96-102, 1980) that catalysts of the Nafion (a trademark) type catalyze the methylation of the ring and the formation of the dimethyl-ether in a mixture of phenols and methanol.
Nothing suggested that the process could follow a quite different course, so as to achieve an almost complete selectivity for the mono-etherification process, under different reaction conditions, in particular as regards the ratios be-tween the reactants and the temperature.
The present invention will be further illustrated, by way of the following Examples.
EXA~PLE 1 125 g ~1.135 moles) of pyrocatechol, 14.5 g (0.454 moles) of methanol and 30.6 g (0.03063 equiv.) of perfluorosul-phonic acid (Nafion 501 a trademark of Du Pont) are placed in a flask equipped with a stirrer, thermometer and reflux conden-ser. The mixture is heated at 120C for 5 hours. After this reaction time, the composition of the mixtures is as follows:
5~3 Unconverted pyrocatechol 87%
Guaiacol 12.8%
Compounds with methyl groups o lQ
on the ring Veratrole 0.1%
The yield of guaiacol on the converted pyrocatechol can be considered almost quantitative.
Operating exactly as previously described, but using as catalyst an ion exchange resin composed of polystyrenesul-phonic acid cross-linked with divinylbenzene (supplied under the trademark Amberlist 15), in an amount corresponding to 0 ~ 03063 acid equiv., a reaction mixture is obtained after 5 hours, having the following composition: _ Unreacted pyrocatechol98.8%
Guaiacol 1.0%
Compounds with methyl groups o 1%
on the ring Veratrole 0.1%
250 g of pyrocatechol (2.27 moles), 36 ~ 3 g of methanol (1.135 moles) and 61n 2 g of Nafion 501 (a trademark) corres-ponding to 0. 0612 acid equiv. are placed in the same flask of Example 1. The mixture is heated at 150 - 155 C for 5 hours.
After this reaction time the composition of the reaction mix-ture is as follows:
Unreacted pyrocatechol80~o Guaiacol 18. 5%
Methylated compounds1~0~o Veratrole o. 5%
107 g of phenol (1.135 moles), 14.5 g of methanol (0.454 moles) and 30.6 g of Nafion 501 (a trademark) (0.03063 equiv.) are placed in the same flask of Example 1. The mixture is heated at 120C for 5 hours. After this time the composi-tion of the reaction mixture is as follows:
Unreacted phenol 85%
Anisole 14.9%
Alkylated products 0.1%
250 g of pyrocatechol (2.27 moles), 3.63 g of methan-ol (0.1135 moles) and 61.2 g of perfluorosulphonic acid (0.0612 acid equiv.) are placed in the same flask of Example 1. The _ mixture is heated at 150-155C for 1 hour and then again 3.63 g of methanol are added. The mixture is further heated at 150-155C for 1 hour and afterwards 3.63 g of methanol are again added, continuing to heat at 150-155C. After 3 hours the mix-ture has the following composition:
Unreacted pyrocatechol 88.6 Guaiacol 11.4 EXA~IPLE 5 125 g of hydroquinone (1.135 moles), 14.5 g of methanol (0.454 moles) and 30.6 g (0.03063 acid equiv.) of Nafion 501 (a trademark of Du Pont), are placed in the same flask of Example 1. The mixture is heated at 120C for 5 hours. After this time the reaction mixture has the following com~osition:
Unreacted hydroquinone 90.5%
Hydroquinone monomethylether 9.4Q
Pxoducts with ring a'kylation 0.1 j ~ .1 '7~
125 g o~ pyrocatechol (1.135 moles), 21 g of ethanol (0.455 moles) and 30.6 g (0.03063 equiv.) of Nafion 501 (a trademark) are placed in the same flask of Example 1. The mixture is heated at 120C for 5 hours. After this time the composition of the mixture is as follows:
Unconverted pyrocatechol 85%
Guetol 14.5%
Other products 0.5%
162 g of ~-naphtol (1.135 moles), 14.5 g of methanol (0.454 moles) and 30.6 g (0.03063 equiv.) of Nafion 501 (a trademark) are placed in the same flask of Example 1. The mixture is heated at 125C for 5 hours. After this time the composition of the mixture resulted to be as follows:
Unconverted ~-naphtol 86%
~-naphtol monomethylether 13.7%
Other products 0.3%
125 g of pyrocatechol (1.135 moles), 14.5 g of methanol (0.454 moles) 0.01 equivalents of Nafion 501 (a trade-mark) and 0.02 equiv. of Amberlist 15 (a trademark) are placed in the same flask of Example 1. The mixture is heated at 125C for 5 hours. After this time the mixture has the follow-ing composition:
Unreacted pyrocatechol 89%
Guaiacol 10.9 Other products 0.1
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of a phenol monoether from a mono- or poly-valent phenol and an aliphatic alcohol, according to the equation:
in which Ar is an aryl radical; R is a C1-C6 aliphatic radical;
n is 1 or 2 in which a mixture of the phenol and aliphatic alcohol is reacted in the presence of a "superacid" as catalyst, at temperatures between 110 and 170°C, with a phenol:alcohol ratio between 2:1 and 6:1.
in which Ar is an aryl radical; R is a C1-C6 aliphatic radical;
n is 1 or 2 in which a mixture of the phenol and aliphatic alcohol is reacted in the presence of a "superacid" as catalyst, at temperatures between 110 and 170°C, with a phenol:alcohol ratio between 2:1 and 6:1.
2. A process according to claim 1, wherein the "superacid" is used in admixture with an acid ion exchange resin.
3. A process according to claim 1, wherein the "superacid" is selected in the group consisting of fluorinated sulphonic acids and perfluorosulphonic resins.
4. A process according to claim 1, 2 or 3, wherein the catalyst is used in an amount of 1-30% by weight based on the weight of reactants.
5. A process according to claim 1, 2 or 3, wherein a solvent for the phenol and alcohol is used, which is inert under the conditions of the reaction.
6. A process according to claim 1, 2 or 3, in which the phenol is selected from phenol, cresol, xylenol, pyrocatechol, hydroquinone, resorcinol and a naphthol and the alcohol is select-ed from methanol and ethanol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT25106/80A IT1132911B (en) | 1980-10-03 | 1980-10-03 | PROCESS FOR THE PREPARATION OF PHENOLIC ETHERS |
| IT25106A/80 | 1980-10-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1173859A true CA1173859A (en) | 1984-09-04 |
Family
ID=11215718
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000387190A Expired CA1173859A (en) | 1980-10-03 | 1981-10-02 | Process for the preparation of phenol ethers |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5791940A (en) |
| BE (1) | BE890589A (en) |
| CA (1) | CA1173859A (en) |
| CH (1) | CH647221A5 (en) |
| DE (1) | DE3139324A1 (en) |
| FR (1) | FR2491457A1 (en) |
| GB (1) | GB2085004B (en) |
| IT (1) | IT1132911B (en) |
| NL (1) | NL8104500A (en) |
-
1980
- 1980-10-03 IT IT25106/80A patent/IT1132911B/en active
-
1981
- 1981-09-30 FR FR8118402A patent/FR2491457A1/en active Granted
- 1981-10-01 BE BE0/206141A patent/BE890589A/en not_active IP Right Cessation
- 1981-10-02 GB GB8129804A patent/GB2085004B/en not_active Expired
- 1981-10-02 JP JP56156309A patent/JPS5791940A/en active Pending
- 1981-10-02 DE DE19813139324 patent/DE3139324A1/en not_active Withdrawn
- 1981-10-02 NL NL8104500A patent/NL8104500A/en not_active Application Discontinuation
- 1981-10-02 CA CA000387190A patent/CA1173859A/en not_active Expired
- 1981-10-02 CH CH6365/81A patent/CH647221A5/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| BE890589A (en) | 1982-02-01 |
| GB2085004B (en) | 1984-11-07 |
| DE3139324A1 (en) | 1982-06-16 |
| GB2085004A (en) | 1982-04-21 |
| CH647221A5 (en) | 1985-01-15 |
| FR2491457A1 (en) | 1982-04-09 |
| IT1132911B (en) | 1986-07-09 |
| JPS5791940A (en) | 1982-06-08 |
| NL8104500A (en) | 1982-05-03 |
| IT8025106A0 (en) | 1980-10-03 |
| FR2491457B1 (en) | 1985-02-15 |
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