RU2137745C1 - Tert-butyl alcohol production process - Google Patents

Abstract

FIELD: industrial organic synthesis. SUBSTANCE: isobutane is subjected to liquid-phase oxidation with oxygen-containing gas at 80 to 200 C and pressure 1.0 to 10.0 MPa in presence of, as catalyst, 0.001 to 0.2% (based on isobutane weight) of coordination complex of substituted metal phthalocyanine having general formula M-L-Rn wherein M is iron, cobalt, nickel, or ruthenium; L phthalocyanine; R tert-butyl, dibutylaminosulfonyl, butulsulfonyloxy, decylsulfonyloxy, or chlorosulfonyl group; n=2-4. As promoter, 0.02 to 2.5 wt % of organic amide can be added. EFFECT: simplified technology. 2 cl, 28 ex

Description

 Tert-butyl alcohol is an important product of petrochemical synthesis and is widely used as a solvent, as a high-octane component of gasoline or as a raw material for MTBE and concentrated isobutylene.

 It is well known that isobutane can be thermally oxidized in the absence of a catalyst to produce a mixture of tert-butyl alcohol and hydroperoxide, as well as small amounts of acetone, methanol, formic acid and tert-butyl peroxide.

 In the presence of soluble cobalt salts, for example cobalt stearate or cobalt naphthenate, isobutane oxidation proceeds faster and leads mainly to tert-butyl alcohol. The disadvantage of this method is the rather low oxidation rate of isobutane to tert-butyl alcohol.

Closest to the proposed is a method for producing tert-butyl alcohol by isobutane oxidation in the presence of phthalocyanines of various metals (Vn, Fe, Co, Cu) at a temperature of 125 ^o C and a pressure of 600 psi (US Pat. No. 3816548 from 11.06.74). Moreover, for 6 hours of the reaction, the conversion of isobutane is 55-61% with a selectivity of tert-butyl alcohol of ~ 80 mol%.

 The disadvantage of this method is that the metal phthalocyanines practically do not dissolve in any organic solvents, which complicates their industrial use. Namely: when using the catalyst in the form of a suspension, the problem of uniform distribution of the catalyst in the reaction volume arises. The use of a catalyst on supports or substrates reduces the useful reaction volume of the oxidation apparatus.

 The problem solved by the invention is to simplify the process technology through the use of soluble catalysts.

 The present invention relates to a method for producing tert-butyl alcohol by liquid-phase oxidation of isobutane with an oxygen-containing gas in a homogeneous phase in the presence of a catalyst, which is a coordination complex of a substituted metal phthalocyanine of group VIII of the Periodic system of elements.

The coordination complex has the general formula:
M - L - R _n ,
where M is a metal (iron, cobalt, nickel or ruthenium);
L is a phthalocyanine ligand;
R is a ligand substituent (-tert-C ₄ H ₉ ; -SO ₂ N (C ₄ H ₉ ) ₂ ; -SO ₂ OC ₄ H ₉ ; -SO ₂ OC ₁₀ H ₂₁ ; -SO ₂ Cl;
n = 2-4.

 The proposed metal complex can be used in a wide range of 0.001-0.2% of the loaded isobutane, preferably 0.005-0.1%.

 To improve the solubility of the catalytic complex, it can be promoted with an amide of an organic acid. As the amide of the organic acid, for example, dimethylformamide can be used. In addition to improving solubility, the promoter increases the rate of formation of tert-butyl alcohol. In this case, the promoting amide additive can be used in an amount of 0.02-2.5 wt.% From isobutane.

 For oxidation, oxygen or an oxygen-containing gas, such as air, can be used. If necessary, you can use an organic solvent, for example tert-butyl alcohol.

 As initiators of the oxidation process, compounds that form free radicals can be used, for example, tert-butyl hydroperoxide in an amount of 0.5-10.0 wt.% Of the loaded hydrocarbon.

The temperature of the oxidation reaction is 50-200 ^° C, preferably 120-150 ^° C, pressure 1.0-10.0 MPa, preferably 3.0-7.0 MPa.

 The process can be carried out both periodically and continuously.

 The oxidation reaction mass contains, along with tert-butyl alcohol, a certain amount of tert-butyl hydroperoxide.

 The decomposition of the residual tert-butyl hydroperoxide can be carried out in the holding zone or by distillative decomposition in the separation of tert-butyl alcohol from the oxidation reaction mass.

 Substituted metal phthalocyanine can be prepared by the methods listed below.

Iron tetra-tert-butylphthalocyanine - FePc (tC ₄ H ₉ ) _{4 was} prepared as follows. First, o-xylene was alkylated, then it was oxidized to acid with its further conversion to anhydride. Further, the obtained anhydride was treated with urea and an iron salt [Bundina N.I., Potassium 0. L., Lebedev 0. L. et al. Coordination chemistry, vol. 2, no. 7, 1976, p. 940-947].

Cobalt dibutyl sulfoammonium phthalocyanine - CoPc [SO ₂ N (C ₄ H ₉ ) ₂ ] _{3-4 was} obtained from cobalt phthalocyanine, which was first chlorinated with chlorosulfonic acid with the further addition of dibutylamine.

The synthesis of butyl and decyl esters of cobalt phthalocyanine disulfonic acid — CoPc (SO ₂ OC ₄ H ₉ ) ₂ and CoPc (SO ₂ OC ₁₀ H ₂₁ ) ₂ — was carried out by reacting cobalt phthalocyanine disulfochloride with the corresponding alcohol in a stream of nitrogen [K. Buhler, D. Pearson , Organic Syntheses, Part 2. - M .: Mir, 1973].

Cobalt phthalocyanine disulfochloride - CoPc (SO ₂ Cl) ₂ - was obtained from cobalt phthalocyanine disulfonic acid and thionyl chloride in the presence of dimethylformamide [L. Fizer, M. Fizer, Reagents for organic synthesis, v.3. - M .: Mir, 1970, p.331].

 The solubility of substituted metal phthalocyanines is improved in the presence of a promoter, an organic amide, for example dimethylformamide.

 The use of the proposed catalysts allows you to maintain a high reaction rate with good selectivity in tert-butyl alcohol.

 Isobutane is loaded into the reactor in an appropriate amount, the catalyst and, if necessary, the initiator and solvent are also loaded there. Oxygen-containing gas is passed continuously through the reaction mixture. Pressure and temperature are maintained at the right level.

 The invention is illustrated in examples 1 to 28. The results are presented in the table.

 In the above examples, isobutane in an amount of 36 g was loaded into a batch reactor with a volume of 0.2 l, the initiator was tert-butyl hydroperoxide (GPTB) in an amount of 1.8 g, the solvent was tert-butyl alcohol (TBS) in an amount of 7.2 g and a catalyst with a promoter.

Air was supplied to the reactor at a rate of 15 l / h. The oxidation reaction time was 3 hours. The reaction temperature is 145 ^o C, a pressure of 5.0 MPa.

Claims (2)

1. The method of producing tert-butyl alcohol by liquid-phase oxidation of isobutane with an oxygen-containing gas at a temperature of 50 - 200 ^o C and a pressure of 1.0 - 10.0 MPa in the presence of a catalyst based on metal phthalocyanine of group VIII of the Periodic system of elements, characterized in that as a catalyst use the coordination complex of the substituted metal phthalocyanine of the general formula
M - L - Rn,
where M is iron, cobalt, nickel or ruthenium;
L is phthalocyanine;
R is tert-C ₄ H ₉ ; -SO ₂ N (C ₄ H ₉ ) ₂ ; -SO ₂ OC ₄ H ₉ ; -SO ₂ OC ₁₀ H ₂₁ ; -SO ₂ CL;
n = 2 - 4,
taken in an amount of 0.001 to 0.2 wt.% from isobutane.  2. The method according to claim 1, characterized in that the promoter is additionally used - an organic amide in an amount of 0.02 - 2.5 wt.% From isobutane.

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