JPS59196838A - Production of tertiary butylbenzoquinone - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an antioxidant, etc., quantitatively, at a low temperature, in high selectivity, by dissolving o-tert-butylphenol in a specific solvent to a specific low concentration, and oxidizing the compound with O2 in the presence of a catalyst such as cuprous chloride. CONSTITUTION:o-ter-Butylphenol is dissolved in a nitrile such as acetonitrile, benzonitrile, etc. or in a mixture of the nitrile and a lower aliphatic alcohol such as methanol, ethanol, etc. or a lower aliphatic ester such as methyl acetate, ethyl acetate, etc., to a concentration of <=20g/1, preferably <=5g/1, and is made to react with O2 under the O2 partial pressure of 2-100kg/cm<2> at -20- +20 deg.C in the presence of CuCl or CuBr catalyst to obtain the objective compound. The solvent is preferably a mixture of a nitrile and an alcohol or an ester to achieve high selectivity. USE:Intermediate for the production of tert-butylhydroquinone, etc.

Description

[Detailed description of the invention]

The present invention relates to a method for producing tertiary-butyl-bala-benzoquinone (hereinafter referred to as TBQ) by oxygen-oxidizing oron-tertiary butylphenol (hereinafter referred to as TBP). TBQ itself is used as an antioxidant, and is also an unnecessary compound as an intermediate in the production of tertiarybutyl/)hydroquino/. In order to produce 14-quinones by acidifying phenols with molecular oxygen, for example, JP-A-52-17432
As shown in the publication, the 2l.
It is said that a method using as a catalyst a copper salt that forms a complex that can be dissolved in the reaction system by coordination with lyle is recommended, and the reaction conditions in this case are a temperature of about 0 to 100 °C and a temperature of about 7 to 200
It is said that the oxygen partial pressure of atmospheric pressure is appropriate. but,
In order to obtain a relatively high selectivity with this method, a reaction temperature of 50°C or higher and an oxygen partial pressure of 20 atmospheres or higher are required, and even then, the formation of tar-like by-products is unavoidable. There are some difficulties. The present inventor attempted this reaction as a method for producing TBQ from TBP, but the selectivity was extremely low at a high reaction temperature of 50° C., and a considerable amount of tar-like byproducts were observed to be produced. As a result of further research, we found that when the original f-+ TBP concentration in the solvent was very diluted to less than 20q-/ and oxidized at a low temperature of -20 to 20℃, an extremely high selectivity was obtained. It was found that this was achieved and the TBQ could be obtained almost in a regular manner. Furthermore, this is specific to TBP, such as TBPs such as phenol, ortho-cresol, 2,6-tert-butylphenol, ortho-methoxyphenol.
With phenol having a substituent at the orne position like BP, such high selectivity could not be achieved by a method similar to the present invention. According to the present invention, T B P is 2) IJ or nitrile and lower fat 11) j Ih, alcohol or lower fat liquid ester in a mixed solvent 20'! -/ is oxidized with oxygen at the following dilute concentration in the presence of a cuprous chloride or cuprous bromide catalyst. explain in detail. Solvents used in the process of the invention include aliphatic di-1-'J, aromatic nitriles such as acetonitrile, propionitrile, butyronitrile, be/sonitrile, tolnitrile,
Benzyl cyanide■ and these and lower aliphatic alcohols, such as methanol, ethanol, propatool,
A mixed solvent with methanol or a lower aliphatic ester such as methyl acetate or ethyl acetate is suitable. Selection of the target product i In terms of raw materials, a mixed solvent with alcohol or ester is better than using nitrile alone, and in that case, the mixing ratio of nitrile: alcohol or haester = 8:2 to 4:6. A range of is suitable. The catalyst can be any copper catalyst, and is limited to cuprous chloride and cuprous bromide. Even with the same cupric halide, cuprous iodide shows no activity, and even with copper chloride and copper bromide, cupric jjllA shows no activity. However, as a method for obtaining cuprous chloride or cuprous bromide as a catalytic active component, it is possible to use a process using equimolar amounts of cupric chloride or cuprous bromide and metallic copper, or alternatively, to obtain cupric chloride or cuprous bromide as a catalytic active component, it is also possible to use a process using equimolar amounts of cupric chloride or cuprous bromide and metallic copper, or to use metallic copper and hydrogen chloride. Or it may be treated with equimolar amount of hydrogen bromide,
Also, during this reaction, metallic copper, cupric chloride, cupric bromide,
Furthermore, even if V5, ferrous chloride, ferric chloride, etc. are mixed and coexist, there is no particular adverse effect on the selectivity of the target product. 1Δj,
As long as the concentration of cuprous chloride and cuprous bromide as a catalyst is within an appropriate range, it will not have any effect on the selectivity of TBQ, but using too large a quantity will be economically disadvantageous. Moreover, it is not preferable because it becomes insoluble in the reaction solution. On the other hand, there are not many
However, in the method of the present invention, the reaction rate is usually 05 to 50%/11, or preferably 5 to 20!, since a practically sufficient reaction rate cannot be obtained with ; -/l is suitable for use. anti-t

[4. Generally, the higher the temperature, the lower the selectivity, but the reaction rate tends to increase. Therefore, the preferable temperature range is -20 to 20'C, and around 0'C is preferable considering the reaction moderation and selectivity. Oxygen gas is used as an oxygen source. In addition, an oxygen-containing gas such as air may be used, but the higher the oxygen partial pressure during the reaction, the better the selectivity, and good results can be obtained from a partial pressure of oxygen of 2 to 7/c?1 or higher. There are no reaction restrictions on the upper limit of oxygen partial pressure, but if it is too high, there will be equipment restrictions, so
Aπ switch is appropriate. But 10 Kg/c
Since T B Q can be obtained stationarily even with an oxygen partial pressure of about 1 degree n'l, a reaction pressure in this vicinity is most preferable. However, stirring efficiency also affects selectivity, so it is necessary to perform effective stirring. In the method of the present invention, the TBP concentration has the greatest influence on the selectivity of the reaction, and if this concentration is high, the selectivity of the target product decreases significantly. It is safe to keep the concentration at most 20 g/ or less, preferably 51/ or less. In such a dilute solution, the productivity of TBQ decreases considerably, but if the quinone accumulation is within the range of 400g-/LL12 or 2007/A, TBQ selection 1 is possible.
Since the ratio does not decrease significantly, productivity can be increased without reducing the selectivity of TBQ by continuously supplying TBP in an amount commensurate with the reacted TBP so that the above conditions are maintained. can. Examples will be given below to explain in more detail. Example] TBP in a 1t glass autoclave 2. OOg'. CuCl2. OOf, acel-=1-lyl 280mt
and methanol at 120 mA, and heated to -5°C at 41.1 mA.
Oxygen pressure 10 kg while strictly controlling 0 degrees
/ ad for 50 hours. After the reaction was completed, the 1-1 TBQ treated with water was extracted with methylene chloride, and the TBQ was purified by column chromatography.
3 Q 2.14.9- (yield 979%). Examples 2 to 10 Reactions were carried out using various alcohols or esters in place of methanol in Example 1. Note that the yield was determined by gas chromatography analysis. Examples 11 to 15 In place of acetonitrile in Example 1, a divine nitrile was used to carry out the reaction. In addition, the yield (according to gas chromatography analysis.
/- instead of 1'cetonitrile/l(1 (I
The reaction was carried out using ml, and 1) 5 meat 11L T B Q 2. 0:
3! /(Figure 1/K'9 29)
I was. [Example I7] In a T-glass autoclave, CuCl 5.0
0g-, acel- = Tolyl 280rnt and methanol 1.20ml, oxygen pressure 2 at 1mc
Set to 0 Kv/cuT and TBP to 1 0 q/hr
The reaction was carried out while feeding at a ratio of Total supply T B
When P reached 801, the supply of TBP was stopped and the reaction was continued for an additional 2 hours. After the reaction is complete, treat with water and
BQ is extracted with methylene chloride and distilled into T B
Q 7 7. sy (yield 890%) was f(I. Comparison V/!1 In a 1t glass autoclave, TBpsoy, CuC7
5007, 280 mt of acetonitrile and 120 mt of Tsukunor. C was mixed with 1 (MC. 9.1g- (yield 6
76), but the generation of tar-like by-products was not observed.

Claims (1)

[Claims] 2077 in a mixed solvent of nitrile or nitrile and lower aliphatic alcohol and lower fatty acid ester at the following dilute concentration. A method for producing tertiary-butyl-C-benzoquinone, which comprises carrying out oxygen oxidation in the presence of a cuprous catalyst.