DE1811443A1 - Process for the production of alkylphenols - Google Patents

Description

Wesseling, November 25, 1968 VP / Dr Sch-B / Ne

Our reference: UK 220

Process for the production of alkylphenols

The present invention relates to a method of manufacture of alkylphenols with a high content of m-isomers through catalytic conversion of phenol with an alkylating agent

The alkylation of phenol with alkyl oxidants, such as olefins, alcohols, ethers or alkyl halides, in the presence of aqueous Solutions of zinc bromide or zinc chloride, optionally with additions of bromine or hydrogen chloride, are known. You get phenols which are generally alkylated in the nucleus, the alkylation taking place primarily in the o- or p-position. It will if appropriate, mixtures of the p- and m-isomers are also obtained, but the p-isomer content then predominates.

It has now been found that alkylphenols with a high content of m-isomers can be obtained from phenol and an alkylating agent in the presence of an aqueous catalyst solution which contains zinc bromide or zinc chloride and is activated by adding small amounts of bromine or hydrogen chloride by alkylation at elevated temperatures up to about 1200 C, and subsequent isomerization may be obtained at temperatures above about I50 ⁰ C, when is separated by distillation, the lower boiling components of the Reaktionsgeiaisches prior to isomerization. The alkylating agents used are expediently compounds which have up to about h carbon atoms in the alkyl groups, but higher alkyl groups can also be used. The zinc bromide or zinc chloride content of the catalyst solution can vary widely. For example, 1 to 10 moles of water can be present per mole of zinc halide. The addition of hydrogen halide is generally 0.1-1.5 moles per mole of zinc halide. Also the amount t: $ :; Tingtettite catalyst solution can be used in a wide range of 3re.na «n« respective; lt «« rdöi:. Asu; üäün z «B · 30 % aad more, based on used; se ä - ;; ^ r.-i. _; vlhlea, but quantities may also be vzz;. U,

009825/2031

Our reference: UK 220

15 % or less is sufficient. The alkylation must first be carried out at the relatively low temperature and then the isomerization of the alkylate obtained at the higher temperature mentioned. The time at which the constituents boiling below the isomerization temperature are separated off by distillation can be chosen differently. A two-way embodiment of the process is that the alkylation is first carried out by reacting phenol with the alkylating agent, ZoB "isobutylene, in the presence of the catalyst solution at, for example," 100-110 ° C. The mixture is then heated slowly to the Isomerisieruxigstemperatur, eg "18Ö ° C, and enrfernt this distillation the boiling below 18O ° C mixture components ,, consisting of water aas the catalyst solution, something isobutylphenol, phenol and hydrogen halide consist ·" After achieving the isomerization is the rearrangement to m- Isoraerem carried out "from the resulting Isomereagemisch the unreacted phenol and .alkylierten Pfeeaole can be cleaned in a known manner" are obtained ad "you are such" B _o sttaaehst once or aehrfach ax water washed to remove the Kat'alys &1; orsubstanzen from them remove "and" then _{ad & E} Bo distilled to the Ifer bonds separated by distillation before the isomerization, ie after When they cool down, an oily layer forms and especially from the geaaaatea © rgaaisehen ¥ connection © nb @ st © hea _s köaaeEi gaiss or partially used for conversion. w <sv & @ n _o The Ifesee that occurred during the separation? can Z ₀ B ₀ with fortail for the üäsda® öer isomers to the lätfersi'ag d @ y ICatalysat © 2 ° sKbstaasen needttst eeglea »This results in sick oiia Wassörteöislauf“ öar di © s © asfe anfallsaSes, aieiifc in Effseiisiaaag tretea lets ο

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The inventive method has the advantage that the need there is no need for a separate concentration of the dilute catalyst solution. In addition, e.g. with the technical Carrying out the process use highly concentrated catalyst solutions, while the otherwise necessary concentration the solubility of the zinc halide is often exceeded and the product which precipitates out is then in the distillation column leads to difficulties'. Apart from these procedural Advantages which the inventive preparation of the alkylates brings with it arise compared to the conventional implementation of the Alkylation with one temperature level increases the yield.

example

It was phenol with propylene in the presence of a catalyst solution, which contained 2.5 moles of water and 0.2 moles of HBr per mole of zinc bromide 110 ° C for 3 hours alkylated · Then the temperature was increased to 160 ° C, with the mixture components boiling up to that point were removed by distillation. The remaining mixture became more Maintained at the isomerization temperature for 10 hours. It was then cooled, washed acid-free with water and broken down into its constituent parts disassembled. Thereafter, the alkylate consisted of

31.0 % unreacted phenol

3 ^, 2 % m-isopropylphenol

13.5 % P- " φ

. 6.2 % ο- "
12.2 % diisopropylphenols, 2.9 % higher alkylated compounds

A similar result was obtained when the amount of catalyst was increased halved and the isomerization temperature was increased to 180 ° C to compensate.

009825/2031

Claims (1)

Claims; 1 »Process for the production of alkylphenols with a high content of m-isomers from phenol and an alkylating agent in the presence of an aqueous catalyst solution which contains zinc bromide or zinc chloride and which is activated by adding small amounts of bromine or hydrogen chloride, by alkylation at elevated temperatures up to about 120 ° C and subsequent isomerization at temperatures above about I5O ⁰ C, optionally at elevated pressures, characterized in that is separated by distillation, the lower boiling components of the reaction mixture before the isomerization · 2 · The method according to claim 1, characterized in that one initially the alkylation is carried out, the reaction mixture obtained is heated to the selected isomerization temperature, which is below This temperature boiling constituents are separated from the reaction mixture by distillation, and the isomerization is then carried out. - ' J5. The method according to claim 1, characterized in that the The mixture of phenol and aqueous catalyst solution is heated to the selected isomerization temperature, which is below this The temperature-boiling constituents are separated from the mixture by distillation, and the remaining mixture is cooled after the alkylating agent has been added alkylated and then isomerized at the elevated temperature. k, process according to claims 1-3, characterized in that the oily layer present in the distillate obtained is wholly or partially fed back to the feed mixture « 009825/2031