A kind of preparation method of hydroquinone

Abstract

The present invention belongs to the technical field of fine chemicals, and specifically relates to a method for preparing hydroquinone. The method comprises the following steps: S1, preparing a supported catalyst bed; S2, loading the catalyst bed prepared in step S1 onto a fixed bed reactor; S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product; S4, the crude product is purified by distillation to obtain products of hydroquinone and catechol; The method for preparing the supported catalyst comprises the following steps: (1) ultrasonically dispersing titanium silicon molecular sieve, diatomaceous earth and sodium silicate into deionized water to form a slurry; then spray granulation, roasting, to obtain product A; (2) then adding product A to a mixed acid solution, then stirring the reaction, filtering, washing, vacuum drying, roasting treatment, to obtain product B; (3) ultrasonically dispersing product B, copper salt, cerium salt and chromium salt into deionized water, drying, roasting, to obtain a supported catalyst. The catalyst of the present invention has excellent conversion rate, yield and life.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemicals and more specifically relates to a method for preparing hydroquinone. Background Art

[0002] Hydroquinone (including hydroquinone and catechol) is an important chemical raw material with a wide range of applications. Hydroquinone, also known as hydroquinone, is widely used as a developer in the photosensitive industry, and is also used as a petroleum anticoagulant, catalytic desulfurizer, etc. Hydroquinone is an important raw material for anthraquinone dyes and azo dyes; it is also an important raw material for antioxidants for flavors and oils; because it is easy to react with peroxide free radicals, it is used as an antioxidant and an inhibitor of auto-oxidation; in addition, hydroquinone and its alkyl compounds are also used as inhibitors for monomer storage and transportation. Catechol, also known as pyrocatechol, is used in medicine, pesticides, spices, photography, resins, coatings and other industries. Guaiacol prepared from catechol is an important raw material for the production of vanillin; tert-butyl catechol prepared from catechol is an inhibitor for butadiene and styrene; synthetic resins made by condensation of catechol and various aldehydes can improve the stability of nylon fibers.

[0003] There are many methods for preparing hydroquinone in the prior art. In recent years, the method of preparing hydroquinone by oxidizing phenol with hydrogen peroxide and hydroxylating it has attracted the attention of experts and scholars because of its simple process and no discharge of three wastes. Since hydroquinone produced by oxidizing phenol is easier to oxidize than phenol, the selection of catalyst and the optimization of the preparation process of hydroquinone are particularly important.

[0004] CN101204667B discloses a metal-modified FSM-16 molecular sieve catalyst and its application in the reaction of synthesizing diphenol from phenol and hydrogen peroxide. The metal used is one or more of iron, copper, manganese, chromium, tungsten, molybdenum, cobalt, vanadium and titanium. The preparation method is as follows: sodium silicate is added to an aqueous solution containing a metal salt, pH value is adjusted with acid, and the mixture is filtered after stirring for a period of time. The filter cake is transferred to an aqueous solution containing a template. After stirring for a period of time, pH value is adjusted with acid and stirred for a period of time, then filtered, dried and calcined to obtain a catalyst. The catalyst preparation method is simple and low in cost. In the reaction of synthesizing diphenol from phenol and hydrogen peroxide, the conversion rate of phenol obtained on the catalyst Fe-FSM-16 is 27.8%, and the total selectivity of diphenol is 96.4%, which can be compared with TS-1 molecular sieve.

[0005] CN107597173B discloses a catalyst for synthesizing hydroquinone from phenol hydroxylation and a preparation method thereof, wherein the catalyst comprises: component A: molecular sieve carrier; the molecular sieve carrier is one of TS-1 or S-1; component B: one or more of calcium, manganese, zirconium, magnesium, cerium, tin, cadmium, molybdenum, and vanadium metals; wherein each of the metals in component B is supported on the skeleton structure of component A in the form of oxides; component B is measured by the weight of metal oxides, and the weight ratio of each component is component A: component B oxide = (75-98): (2-25). The active components of the catalyst of the present invention are evenly distributed, and when catalyzing phenol to prepare hydroquinone, the phenol conversion rate and hydroquinone selectivity are both high, and the stability is high, and the catalyst can be reused.

[0006] CN115448818A discloses a method for preparing hydroquinone. The method uses α,α-dimethylbenzyl alcohol, a by-product component of the propylene oxide process of the cumene co-oxidation method, as a raw material, and prepares hydroquinone (including hydroquinone, catechol and resorcinol) through hydroxylation, oxidation and cracking steps. The method has a simple route and mild process conditions, and can simultaneously obtain hydroquinones with three structures of o-, m- and p-, thereby realizing high added value utilization of by-product components and having excellent industrial application prospects.

[0007] However, the existing preparation process conditions have problems such as low single-pass conversion rate, poor selectivity for catechol, low ratio of p- / o-catechol, and short catalyst life. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the defects and deficiencies in the prior art and provide a method for preparing hydroquinone. The method comprises the following steps: S1, preparing a supported catalyst bed; S2, loading the catalyst bed prepared in step S1 onto a fixed bed reactor; S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product; S4, the crude product is purified by distillation to obtain products of hydroquinone and catechol; the method for preparing the supported catalyst comprises the following steps: (1) ultrasonically dispersing titanium silicon molecular sieve, diatomaceous earth and sodium silicate into deionized water to form a slurry; then spray granulation, roasting, to obtain product A; (2) then adding product A to a mixed acid solution, then stirring the reaction, filtering, washing, vacuum drying, roasting treatment, to obtain product B; (3) ultrasonically dispersing product B, copper salt, cerium salt and chromium salt into deionized water, drying, roasting, to obtain a supported catalyst. The catalyst of the present invention has excellent conversion rate, yield and life.

[0009] The purpose of the present invention is to provide a method for preparing hydroquinone.

[0010] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0011] A method for preparing hydroquinone comprises the following steps:

[0012] S1, preparing a supported catalyst bed;

[0013] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0014] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0015] S4, the crude product is purified by distillation to obtain products of hydroquinone and catechol;

[0016] The preparation method of the supported catalyst comprises the following steps:

[0017] (1) ultrasonically dispersing titanium silicon molecular sieve, diatomaceous earth and sodium silicate into deionized water to form a slurry; then spray granulating and calcining to obtain product A;

[0018] (2) adding product A to the mixed acid solution, stirring the mixture for reaction, filtering, washing, vacuum drying, and calcining to obtain product B;

[0019] (3) Ultrasonic dispersion of product B, copper salt, cerium salt and chromium salt in deionized water, drying and calcining to obtain a supported catalyst.

[0020] Preferably, the reaction temperature of the aqueous solution of phenol and hydrogen peroxide entering the catalyst bed is 20-60° C. and the pressure is 0.1-5 MPa.

[0021] Preferably, the phenol air velocity is 0.1-2h -1 The molar ratio of phenol: hydrogen peroxide (30%) is 1 to 3:1, and the mass concentration of phenol is 6-8%.

[0022] Preferably, in step (1), the mass ratio of the titanium silicon molecular sieve, diatomaceous earth, sodium silicate and deionized water is 1:0.2-0.6:0.06-0.12:10-14; and the calcination is performed at 600-800°C for 8-14h.

[0023] Preferably, in step (2), the mixed acid consists of hydrochloric acid and acetic acid.

[0024] Preferably, in step (2), the mass ratio of the product A to the mixed acid solution is 1:5-9; in the mixed acid solution, the molar concentration of hydrochloric acid is 2-4 mmol / L, and the concentration of acetic acid is 1-3 mmol / L.

[0025] Preferably, in step (2), the stirring reaction is: stirring the reaction at 80-120°C for 3-7h, the vacuum drying is: vacuum drying at 60-80°C for 6-12h; and the calcination is: calcination at 500-600°C for 4-6h.

[0026] Preferably, in step (3), the ratio of the product B, copper salt, cerium salt and chromium salt is 10 g: 2-4 mmol: 3-5 mmol: 1-3 mmol.

[0027] Preferably, in step (3), the copper salt is at least one of copper nitrate, copper chloride and copper acetate; the cerium salt is at least one of cerium nitrate, cerium chloride and cerium acetate; and the chromium salt is at least one of chromium nitrate, chromium chloride and chromium acetate.

[0028] Preferably, in step (3), the drying is: drying at 100-140° C. for 10-16 h; and the calcining is: calcining at 500-600° C. for 8-14 h.

[0029] The present invention has the following beneficial effects:

[0030] (1) By using a composite carrier, the catalytic performance of the active component can be significantly improved and the life of the catalyst can be improved.

[0031] (2) Through mixed acid treatment and the interaction of active components, the overall performance and life of the catalyst are improved.

[0032] (3) The preparation process of the present invention is simple, cheap and readily available, and is conducive to industrial production. DETAILED DESCRIPTION

[0033] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0034] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0035] Example 1

[0036] A method for preparing hydroquinone comprises the following steps:

[0037] S1, preparing a supported catalyst bed;

[0038] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0039] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0040] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0041] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0042] The preparation method of the supported catalyst comprises the following steps:

[0043] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0044] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0045] (3) 10 g of product B, 3 mmol of copper nitrate, 4 mmol of cerium chloride and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0046] Example 2

[0047] A method for preparing hydroquinone comprises the following steps:

[0048] S1, preparing a supported catalyst bed;

[0049] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0050] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0051] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0052] Reaction temperature 60℃; pressure 0.1MPa; (1kg catalyst loading), phenol space velocity 2h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 1:1, the mass concentration of phenol is 8%;

[0053] The preparation method of the supported catalyst comprises the following steps:

[0054] (1) 10 g of titanium silicate molecular sieve, 6 g of diatomaceous earth and 0.6 g of sodium silicate were ultrasonically dispersed in 140 g of deionized water to form a slurry; then spray granulation was performed and calcined at 800° C. for 8 h to obtain product A;

[0055] (2) Then add 10g of product A to 90g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 4mmol / L, and the concentration of acetic acid is 1mmol / L. Then stir and react at 120°C for 3h, filter, wash, vacuum dry at 80°C for 6h, and calcine at 600°C for 4h to obtain product B;

[0056] (3) 10 g of product B, 4 mmol of copper chloride, 3 mmol of cerium acetate and 3 mmol of chromium nitrate were ultrasonically dispersed in 100 mL of deionized water, dried at 140° C. for 10 h, and calcined at 600° C. for 8 h to obtain a supported catalyst.

[0057] Example 3

[0058] A method for preparing hydroquinone comprises the following steps:

[0059] S1, preparing a supported catalyst bed;

[0060] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0061] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0062] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0063] Reaction temperature 20℃; pressure 5MPa; (1kg catalyst loading), phenol space velocity 0.1h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 3:1, the mass concentration of phenol is 6%;

[0064] The preparation method of the supported catalyst comprises the following steps:

[0065] (1) 10 g of titanium silicate molecular sieve, 2 g of diatomaceous earth and 1.2 g of sodium silicate were ultrasonically dispersed in 100 g of deionized water to form a slurry; then spray granulation was performed and calcined at 600° C. for 14 h to obtain product A;

[0066] (2) Then 10g of product A was added to 50g of mixed acid solution, wherein the mixed acid was composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid was 2mmol / L, and the concentration of acetic acid was 3mmol / L. Then, the mixture was stirred at 80°C for 7h, filtered, washed, vacuum dried at 60°C for 12h, and calcined at 500°C for 6h to obtain product B;

[0067] (3) 10 g of product B, 2 mmol of copper acetate, 5 mmol of cerium nitrate and 1 mmol of chromium chloride were ultrasonically dispersed in deionized water, dried at 100° C. for 16 h, and calcined at 500° C. for 14 h to obtain a supported catalyst.

[0068] Comparative Example 1

[0069] A method for preparing hydroquinone comprises the following steps:

[0070] S1, preparing a supported catalyst bed;

[0071] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0072] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0073] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0074] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0075] The preparation method of the supported catalyst comprises the following steps:

[0076] (1) 14 g titanium silicon molecular sieve and 1 g sodium silicate were ultrasonically dispersed in 120 g deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0077] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0078] (3) 10 g of product B, 3 mmol of copper nitrate, 4 mmol of cerium chloride and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0079] Comparative Example 2

[0080] A method for preparing hydroquinone comprises the following steps:

[0081] S1, preparing a supported catalyst bed;

[0082] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0083] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0084] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0085] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0086] The preparation method of the supported catalyst comprises the following steps:

[0087] (1) 14 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0088] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0089] (3) 10 g of product B, 3 mmol of copper nitrate, 4 mmol of cerium chloride and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0090] Comparative Example 3

[0091] A method for preparing hydroquinone comprises the following steps:

[0092] S1, preparing a supported catalyst bed;

[0093] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0094] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0095] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0096] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1, the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0097] The preparation method of the supported catalyst comprises the following steps:

[0098] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0099] (2) Then 10 g of product A was added to 70 g of hydrochloric acid solution, wherein the molar concentration of the hydrochloric acid was 5 mmol / L, and then stirred at 100° C. for 5 h, filtered, washed, vacuum dried at 70° C. for 10 h, and calcined at 550° C. for 5 h to obtain product B;

[0100] (3) 10 g of product B, 3 mmol of copper nitrate, 4 mmol of cerium chloride and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0101] Comparative Example 4

[0102] A method for preparing hydroquinone comprises the following steps:

[0103] S1, preparing a supported catalyst bed;

[0104] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0105] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0106] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0107] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0108] The preparation method of the supported catalyst comprises the following steps:

[0109] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0110] (2) Then 10 g of product A was added to 70 g of acetic acid solution, wherein the concentration of the acetic acid was 5 mmol / L, and then stirred at 100° C. for 5 h, filtered, washed, vacuum dried at 70° C. for 10 h, and calcined at 550° C. for 5 h to obtain product B;

[0111] (3) 10 g of product B, 3 mmol of copper nitrate, 4 mmol of cerium chloride and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0112] Comparative Example 5

[0113] A method for preparing hydroquinone comprises the following steps:

[0114] S1, preparing a supported catalyst bed;

[0115] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0116] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0117] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0118] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0119] The preparation method of the supported catalyst comprises the following steps:

[0120] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0121] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0122] (3) 10 g of product B, 7 mmol of copper nitrate and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0123] Comparative Example 6

[0124] A method for preparing hydroquinone comprises the following steps:

[0125] S1, preparing a supported catalyst bed;

[0126] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0127] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0128] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0129] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0130] The preparation method of the supported catalyst comprises the following steps:

[0131] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0132] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0133] (3) 10 g of product B, 7 mmol of cerium chloride and 2 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0134] Comparative Example 7

[0135] A method for preparing hydroquinone comprises the following steps:

[0136] S1, preparing a supported catalyst bed;

[0137] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0138] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0139] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0140] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0141] The preparation method of the supported catalyst comprises the following steps:

[0142] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0143] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0144] (3) 10 g of product B, 3 mmol of copper nitrate and 6 mmol of cerium chloride were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0145] Comparative Example 8

[0146] A method for preparing hydroquinone comprises the following steps:

[0147] S1, preparing a supported catalyst bed;

[0148] S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor;

[0149] S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product;

[0150] S4. The crude product is purified by distillation to obtain products of hydroquinone and catechol.

[0151] Reaction temperature 40℃; pressure 2MPa; (1kg catalyst loading), phenol space velocity 0.5h -1 , the molar ratio of phenol: hydrogen peroxide (30%) = 2:1, the mass concentration of phenol is 7%;

[0152] The preparation method of the supported catalyst comprises the following steps:

[0153] (1) 10 g of titanium silicate molecular sieve, 4 g of diatomaceous earth and 1 g of sodium silicate were ultrasonically dispersed in 120 g of deionized water to form a slurry; then spray granulation was performed and calcined at 700° C. for 12 h to obtain product A;

[0154] (2) Then 10g of product A is added to 70g of mixed acid solution, wherein the mixed acid is composed of hydrochloric acid and acetic acid, wherein the molar concentration of hydrochloric acid is 3mmol / L, and the concentration of acetic acid is 2mmol / L. Then the mixture is stirred at 100°C for 5h, filtered, washed, vacuum dried at 70°C for 10h, and calcined at 550°C for 5h to obtain product B;

[0155] (3) 10 g of product B, 3 mmol of copper nitrate and 6 mmol of chromium acetate were ultrasonically dispersed in 100 mL of deionized water, dried at 120° C. for 14 h, and calcined at 550° C. for 12 h to obtain a supported catalyst.

[0156] The specific test results of Examples 1-3 and Comparative Examples 1-8 are shown in Table 1:

[0157] Table 1

[0158]

[0159] It can be seen from Table 1 that the method for preparing hydroquinone of the present invention has excellent selectivity and conversion rate, relatively high utilization rate of hydrogen peroxide, relatively long catalyst life, and excellent application prospects.

[0160] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing hydroquinone, characterized in that: The steps include: S1, preparing a supported catalyst bed; S2, loading the catalyst bed prepared in step S1 into a fixed bed reactor; S3, an aqueous solution of phenol and hydrogen peroxide enters the catalyst bed to obtain a crude product; S4, the crude product is purified by distillation to obtain products of hydroquinone and catechol; The preparation method of the supported catalyst comprises the following steps: (1) ultrasonically dispersing titanium silicate, diatomaceous earth and sodium silicate into deionized water to form a slurry; Then spray granulation and roasting are carried out to obtain product A; (2) adding product A to the mixed acid solution, stirring for reaction, filtering, washing, vacuum drying, and calcining to obtain product B; (3) ultrasonically dispersing the product B, copper salt, cerium salt and chromium salt into deionized water, drying and calcining to obtain a supported catalyst; in step (1), the mass ratio of the titanium silicon molecular sieve, diatomaceous earth, sodium silicate and deionized water is 1:0.2-0.6:0.06-0.12:10-14; the calcination is performed at 600-800°C for 8-14h; In step (2), the mixed acid is composed of hydrochloric acid and acetic acid; the mass ratio of the product A to the mixed acid solution is 1:5-9; in the mixed acid solution, the molar concentration of hydrochloric acid is 2-4 mmol / L, and the concentration of acetic acid is 1-3 mmol / L; In step (3), the ratio of the product B, copper salt, cerium salt and chromium salt is 10 g: 2-4 mmol: 3-5 mmol: 1-3 mmol; The phenol space velocity is 0.1-2h -1 The molar ratio of phenol: 30% hydrogen peroxide is 1-3:1, and the mass concentration of phenol is 6-8%.

2. The preparation method according to claim 1, characterized in that: The reaction temperature of the aqueous solution of phenol and hydrogen peroxide entering the catalyst bed is 20-60° C. and the pressure is 0.1-5 MPa.

3. The preparation method according to claim 1, characterized in that: In step (2), the stirring reaction is: stirring the reaction at 80-120°C for 3-7h, the vacuum drying is: vacuum drying at 60-80°C for 6-12h; and the calcination is: calcination at 500-600°C for 4-6h.

4. The preparation method according to claim 1, characterized in that: In step (3), the copper salt is at least one of copper nitrate, copper chloride and copper acetate; the cerium salt is at least one of cerium nitrate, cerium chloride and cerium acetate; and the chromium salt is at least one of chromium nitrate, chromium chloride and chromium acetate.

5. The preparation method according to claim 1, characterized in that: In step (3), the drying is: drying at 100-140° C. for 10-16 hours; and the calcining is: calcining at 500-600° C. for 8-14 hours.

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