CS227544B1 - Method of preparing tert.butylated phenol and/or alkylphenol - Google Patents

Abstract

The invention relates to a process for the production of tert-butylated phenol, but in particular tert-butylated alkylphenols e.g. 2,6-di-tertbutyl-4-methylphenol using wider assortment of petrochemical products such as teic-butylating agents. respectively. donors pure isobutene. Tert-butylation of phenols according to < tb >. The invention is realized in particular in the liquid phase under catalytic action apiothiocohes or protenic acids, wherein tert-butylating agents are used alkyl tert-butyl ethers, preferably methyl tert-butyl ether or isobutyl tert-butyl ether. As a tert-butylating agent tert-butyl alcohol may also be used or an aqueous solution thereof. Alkyl tert-butyl ether, or tert-butylalkghol sa decomposes at a temperature of 7θ to 240 ° C catalytic effect of acids, preferably strong-acid contact. Alcohol produced or water from the reaction product isobutene with admixtures of the decomposed ether and the resulting alcohol and diisobutenes are fed to an alkylarium phenols.

Description

The present invention provides a process for the preparation of tert-butylated phenol, in particular tert-butylated alkylphenols, for example 2,6-di-tert-butyl-4-methylphenol, using a wide variety of petrochemical products as tertiary surfactants or pure isobutene donors.

It has long been known that tert-butylation of phenol with isobutanol or tert-butyl alcohol in the liquid phase under the catalytic action of strong mineral acids such as sulfuric acid, then zinc chloride, other strongly acidic cation exchangers and the like. Liebmann A: Ber. 14, 1842 (1881); Ber. 1 £. 547 (1882); Belov PS et al .: Chim. protnyšl. 1962, No. 7, 470; Žur. prikl. chim. J2, 10 (1962); US Pat. 2,923,745; 2,739,172 and 3,267,154; V. Brit. U.S. Pat. However, there is considerable consumption of catalysts. Better results are obtained with isobutene. Namethin NS et al., Neftechimija 14, 121 (1974) US Pat. 2,544 8.18; Petro M .: Candidate Dissertation Faculty of Chemical Technology SVŠT Bratislava (l ₉₇ 8) J. In this case, a suitable catalyst for the ortho-tert-butyl phenol is mainly aluminum phenolate 1 Kelke et al., J. Org. Chem. 21, 712 (1956) J. In the memory phase or on the scrubbed alkylation catalysts, a mixture of C 1-6 alkenes, such as de-butadiene-pyrolysis C 4 -fracoia (cf. author's certificate 202 461) as well as alkyl tert-butyl ethers and tert-butyl alcohol, can even be used as isobutene donor. However, in the first case there is a problem with the separation or utilization of residual C 1 -fraction (after the isobutene has reacted) and the second method is poorly effective for carrying out the tert-butylation of the phenols in the liquid phase.

In the liquid phase, for reasons of equilibrium as well as greater hydrophilicity to the alcohol-generated catalyst, or even water, as opposed to isobutene, which is much more hydrophobic, tert-butylate proceeds slowly and with low selectivity.

So he uses the advantages of known methods and solves problems (

The production method according to the invention.

According to the invention, a process for the preparation of tert-butylated phenol and / or alkylphenol by tert-butylation with isobutene at a temperature of 30 to 250 ° C under the catalytic action of strongly acidic alkylation catalysts or aluminum compounds at a total pressure of 0.05 to 5 optionally in the presence of solvents is carried out. that at least one compound of the general formula

Wherein R 'is H or C1-C4 alkyl decomposes at 70 to 240 ° C under the catalytic action of a liquid and / or solid strong acid, the water and / or alcohol formed separated by and the isobutene is led to the tert-butylation of phenol and / or alkylphenol, the tert-butylated phenol and / or alkylphenol formed is separated and the unconverted starting materials are optionally recovered.

An advantage of the production method of the present invention and the present invention is the broader choice of starting tert-butylation reagents, precursors, and tone generation. Furthermore, the possibility of * exploiting 'after a small Teohnic addition to the existing phenol tert-butylation manufacturing plant. Then simple handling and technically undemanding storage of the raw materials that do not require pressure tanks. Capokon, high reaction rate and selectivity of phenol tert-butylation and complete reliability of production.

The tert-butylation of the phenols according to the invention is carried out mainly in the liquid phase. Although it can be carried out in the vapor phase or in the trickle-down reactor, its advantages are not so prominent in such processes.

The tert-butylation catalysts used are aprotic, but mainly protonic acids. These include, in particular, aluminum chloride, a complex formed from aluminum chloride and alkylaromates, boron trifluoride, phosphoric acid, p-toluenesulphonic acid, hydrofluoric acid, but mainly sulfuric acid. More recent catalysts are sulfonated polyraers and copolyraers, such as sulfonated copolymers of styrene-divinylbenzene resins, sulfonated phenol-formaldehyde resins, i.e., cation exchangers in H-form, phosphorus pentoxide alone or on carriers, bleaching active clay and especially active polyesters together with acids and polyphosphates. finally aluminosilicates, especially synthetic zeolites. A particularly suitable catalyst is also aluminum phenolate, especially if it is intended to alkylate the phenols at positions 2 and 6,

Isobutene donors according to the present invention are methyl tert-butyl ether, ethyl tert-butyl ether, isopropyl tert-butyl ether, n-propyl tert-butyl ether, n-butyl tert-butyl ether, sec-butyl tert-butyl ether, but in particular isobutyl- tert-butyl ether, which can generate from 1 mole to 2 moles of isobutene and tert-butyl alcohol. The latter can also be applied in the form of an aqueous solution or a solution of another solvent. Said ethers may also be applied dissolved in organic solvents.

Suitable catalysts for the decomposition of the alkyl tert-butyl ethers and tert-butyl alcohol are also the tert-butylation catalysts mentioned above, but heterogeneous catalysts or the most preferred catalysts are suitable. From the technical and economic point of view, cation exchangers in the H-form, furthermore solid phosphate catalysts, in particular polyphosphoric acids and phosphorus pentoxide on supports, are activated by synthetic and natural zeolites.

When decomposing alkyl tert-butyl ethers or tert-butyl alcohol, care must be taken to separate the alcohol or water, since their possible presence in the isobutene slows the tert-butylation rate and decreases the selectivity, as is evident from comparing Example 4 with Examples 1-3. .

Pure tert-butylphenols are usually isolated from the crude tert-butylphenol or alkylphenol by distillation, most often under reduced pressure, e.g., film evaporation is suitable. Less suitable but useful extractions are zone melting and freeze-drying methods.

- 4,227,544

The production method according to the invention can be carried out batchwise, but semi-continuous and continuous production is more suitable,

Further details of the production method as well as advantages are evident from the examples.

Example 1

For a reactor head made of refractory glass having a length of 500 mm and an inner diameter of 30 mm containing 5 cm @ 2 of a phosphate catalyst having a grain size of 0.5 to 2 mm, containing 22.6% by weight. of phosphorus and an acid number of 298 mg KOH / g, over which a layer of 50 cnP Rashig rings is fed, methyl terobutyl ether with a purity of 99% by weight is fed. in the amount of 7.6 g.h ’'* *. The reactor was tempered with a resistance electric heating jacket to 140 ° C. The reaction product leaving the reactor was cooled with a water condenser and the condensed fractions were collected in a trap. The non-condensed vapors are fed to the bottom of a 250 cm @ 3 three-necked flask equipped with a stirrer and a thermometer in which 50 g of p-cresol having a purity of 98% by weight are introduced. and 0.75 g of sulfuric acid with a concentration of 98% by weight. The contents of the flask are tempered to a temperature of 78 ° C. After 16 h the contents of the flask were cooled, weighed and analyzed. 104 g of crude product are obtained with a content of 88% by weight.

2,6-di-tert-butyl-4-methyl-phenol. It is trapped in the trap

48.7 S of a liquid product having a composition (% by weight): 10.26 isobutene; 12.33 methyl tert-butyl ether 2.91 diisobutenes and 74.50 methanol. From the crude alkylated product, sulfuric acid was removed by washing with water and pure 2,6-di-tert-butyl-4-methylphenol was obtained by crystallization twice from ethanol twice. Ethanol is recovered from the mother liquors by distillation. The distillation residue after ethanol recovery is subjected to vacuum distillation. The obtained mono-tert-butyl-p-cresol and di-tert-butyl-p-cresol go back to alkylation.

- 5 227 544

In the second case, at the bottom of the three-necked flask of volume ^a

250 cc containing 50 g of p-cresol 0.75 with sulfuric acid at a concentration of 98 wt · $ fed commercial pure isobutene in an amount of 5 »07 gh @ ^-1 for l4 hours. The tert-butylation also takes place at a temperature of 78 ° C * 2. After 14 h, 107.4 g of alkylated phenols containing 87.3% by weight of 2,6-di-tert-butyl-4-methylphenol are obtained.

Example 2

The procedure is similar to that of Example 1, except that the temperature of the reactor is raised to 150 * 2 ° C and 5S of water is introduced into the separator downstream of the methyl tert-butyl ether decomposition reactor. 106 g of a crude product with a content of 94% by weight are obtained. Of 2,6-di-tert-butyl-4-methylphenol and the isobutene content in the trap separates to 3.5% by weight.

Example 3

The procedure is similar to that of Example 1, except that 10 cm @ 3 of the catalyst specified in Example 1 are placed in the methyl tert-butyl ether decomposition reactor and the temperature of the p-cresol tert-butylation reaction flask is 100 ± 2 ° C. At the head of the decomposition reactor, methyl tert-butyl ether is fed at 16.4 gh ^-1 . After 9 h of t-butylation of p-cresol, 103 S of a crude product containing 89% by weight are obtained. 2,6-di-tert-butyl-4-methylphenol. The separator retains 63.5 S of liquid product of composition ($ w / w):

10.42 isobutene; 7.66 methyl tert-butyl ether; 10.62 diisobutenes and 71.32 methanol.

- 4 Example 4

227 544

The procedure is similar to that in Example 3, except that methyl tert-butyl ether is fed to the top of the reactor in an amount of 17.4 gh. The reaction product leaving the reactor was not quenched with a water cooler, but was fed directly to the bottom of a 250 cm @ 3 three-necked flask with a temperature of 140 ± 5 ° C. After 9 h, 69 ₁ 6 S of alkylated product containing 4 wt.

2,6-di-tert-butyl-4-methylphenol. In a -60 ° C freezer downstream of the reaction tert-butylation flask, 76.5 g of product (wt.): 47.8 isobutene; 3,6 methyl tert-butyl ether;

6.4 diisobutenes, 42.3 methanol. From this, it is evident that the p-cresol tert-butylation rate is significantly lower than that of the intermediate isolation of alcohol or water shown in Examples 1, 2 and 5.

Example 5

Pre-contact with condensate and separator is preceded in front of a 250 µm alkylation three-necked flask containing 50 g of β-cresol and 0.75 g of concentrated sulfuric acid. 10 cnP of a grained, strongly acidic cation exchanger based on sulfonated divinylbenzene-styrene resin (Ostion KS) is placed in the pre-contact and tempered to a temperature of 105 * 2 ° c; % butyl alcohol containing 5.7 wt. water. After the precontact in the water cooler, both the dissolved and reaction water and the unconverted tert-butyl alcohol condensate, which are collected in a trap and the isobutene is led to the bottom of the alkylation flask, where the t-butylation of p-cresol takes place. The crude product obtained in an amount of 104.5 g contains 89.5 wt. 2,6-di-tert-butyl-4-methylphenol.

- 7 Example 6

227 544

In front of a 250 cnP three-necked alkylation flask containing 50 g of β-cresol and 0.75 S of sulfuric acid at a concentration of 98% by weight. Pre-contact with condenser and separator is preceded. 10 cm @ 3 of the faujasit HY-type activated activated zeolite change 0.5 to 1.5 mm, which is heated to 175 * 2 ° C. This catalyst was fed over 9 hr GH ¹ 20 isobutyl tert-butyl ether. In the water cooler, mainly the unconverted ether and some of the isobutanol are collected, which are collected in a trap and the isobutene is next to the bottom of the alkylation flask, where the t-butylation of p-cresol takes place at 100 ° C. The crude product obtained in the tan of 107 S contains 92% by weight. 2,6-di-tert-butyl-4-methylphenol.

In dalšora experiment under otherwise similar conditions is added a 15 gh isobutyl tert-butyl ether, but the addition of 5 ¹ of a solution containing GH 16 # isobutene diizobuténov 19 #, 23% isobutanol and 58% isobutyl tert-butyl ether. The crude product obtained in an amount of 106.5 g contains 92% by weight. 2,6-di-tert-butyl-4-methylphenol.

Claims (2)

Process for the preparation of tert-butylated phenol and / or alkylphenol with tert-butyl isobutone at a temperature of 30 to 250 ° C under the catalytic action of strongly acidic alkylation catalysts or aluminum compounds, at a total pressure of 0.05 to 5 MPa, optionally in the presence of solvents; in that at least one compound of the formula R ROCHCHCH) in which R 'is H or alkyl having 1 to 4 carbon atoms decomposes at a temperature of 7 ° to 240 ° C under the catalytic action of liquid and / or solid saline acid, wherein the formed water and / or alcohol is separated with an efficiency of 50 to 100% and the isobutene is separated in addition to the tert-butylation of phenol and / or alkylphenol, the formed tert-butylated phenol and / or alkylphenol is separated and unconverted starting materials optionally recovered. 2. A method according to claim 1, characterized in that at least one compound of the formula ROC (CH3) 4 is methyl tert-butyl ether, isobutyl tert-butyl ether or tert-butyl alcohol.