CN100391600C

CN100391600C - Catalyst for synthesizing methyl carbonate and method for preparing the same

Info

Publication number: CN100391600C
Application number: CNB2006100126664A
Authority: CN
Inventors: 李忠; 任军; 谢克昌
Original assignee: Taiyuan University of Technology
Current assignee: Taiyuan University of Technology
Priority date: 2006-04-30
Filing date: 2006-04-30
Publication date: 2008-06-04
Anticipated expiration: 2026-04-30
Also published as: CN1843621A

Abstract

The present invention relates to a catalyst for synthesizing dimethyl carbonate (DMC) and a preparation method thereof. The catalyst is a reaction catalyst which uses methanol to synthesize DMC by way of oxidative carbonylation, and belongs to the field of heterogeneous catalysis in chemical industry. The present invention is characterized in that the catalyst is prepared by combining the methods of liquid phase precipitation, crystallization and water washing and takes copper chloride hydroxide (Cu2(OH)3Cl) as a main constituent. In the specific preparation process, copper chloride is reacted with cupric oxide, sodium hydroxide or ammonia water, Cu2(OH)3Cl is generated and crystallized under proper conditions, the pH value range is 7.0 to 10.0, and the temperature 40 to 80 DEG C; catalysts containing 60 to 95% of Cu2(OH)3Cl are obtained after the crystallized Cu2(OH)3Cl is purified by way of water washing. The catalyst is used in the reaction using methanol to synthesize DMC by way of oxidative carbonylation, and high catalytic activity and selectivity can be obtained. The space time yield of DMC can be as high as 0.3 to 0.9 kg/kg. h, and the selectivity to DMC is as high as 60 to 98%.

Description

The Catalysts and its preparation method of Synthesis of dimethyl carbonate

One, technical field

The Catalysts and its preparation method of Synthesis of dimethyl carbonate of the present invention, be a kind of be the Catalysts and its preparation method of the methanol vapor phase/liquid-phase oxidative carbonylation method Synthesis of dimethyl carbonate (DMC) of main active constituent with γ-basic copper chloride, belong to the heterogeneous catalysis technology field of chemical.

Two, background technology

Dimethyl carbonate (Dimethyl Carbonate, be called for short DMC) be considered to one of most important green chemical industry product of 21 century, can replace as intermediate that severe toxicity such as phosgene, dimethyl suflfate, chloromethanes and methylchloroformate or cancer-causing chemicals carry out carbonylation, methylate at numerous areas, organic synthesis such as esterification and ester exchange; In addition because its good dissolubility and rich oxygen content also can be used as high-quality solvent and fuel oil additive.Because phosgenation technology has serious harm to environment and personnel at present, the clean study on the synthesis of relevant DMC has caused extensive concern both domestic and external in recent years, wherein oxidative carbonylation of methanol method is a raw material with methyl alcohol, carbon monoxide, be respectively the important Coal Chemical Industry product and the Main Ingredients and Appearance of coal gasification, meeting China is the chemical industry route of raw material with the abundant coal of relative reserves, have that technology is simple, catalyst is easily separated, operating pressure is low and does not have advantage such as hidden peril of explosion, industrial applications has a extensive future.With the basic copper chloride is active catalyst, has the reactivity height, good stability, the advantage that equipment corrosion is little.

At present, the catalyst of the synthetic DMC of methanol vapor phase/liquid-phase oxidative carbonylation method mainly is divided into three kinds:

1) Cu (I) is catalyst based.With CuCl catalyst or CuCl supported catalyst.

2) Cu (II) is catalyst based.Support type CuCl ₂Catalyst.

3) dual-component catalyst.Be mainly two component loading type Pd Cl ₂-CuCl ₂Catalyst.

These catalyst since in the course of reaction Cl run off gradually, the life-span is very short, the HCl gas of separating out also can severe corrosion equipment; And along with the carrying out of reaction, catalyst surface Cl runs off gradually, and copper is converted into CuO or crosses copper oxychloride such as Cu ₂O _3/2Cl and loss of activity.

Three, summary of the invention

The Catalysts and its preparation method of Synthesis of dimethyl carbonate of the present invention, it is the technical scheme of the new catalyst and preparation method thereof of main component with γ-basic copper chloride that purpose is to disclose a kind of, thereby a kind of catalyst activity and selectivity that not only has the synthetic DMC of higher methanol oxidation carbonylation is provided, and the new catalyst little to equipment corrosion.

The catalyst of Synthesis of dimethyl carbonate of the present invention, it is characterized in that it being a kind of catalyst by the synthetic dimethyl carbonate of methanol oxidation carbonylation, this catalyst is main active constituent with γ-basic copper chloride, with copper chloride and cupric oxide, NaOH or ammoniacal liquor reaction, control pH value of solution value scope is 7.0～10.0, temperature is 40～80 ℃, generate the basic copper chloride crystallization gradually, wash purification then, obtain containing the catalyst of 60～95% γ-basic copper chloride, the dimethyl carbonate space-time yield that is used for the acquisition of methanol oxidation carbonylation is 0.3～0.9kg/kgh, and selectivity reaches 60%～98%.

The catalyst of above-mentioned a kind of Synthesis of dimethyl carbonate, the crystal structure that it is characterized in that described basic copper chloride catalyst is γ-Cu ₂(OH) ₃Cl, JCPDS card number are 25-1427, monoclinic form.

The Preparation of catalysts method of above-mentioned Synthesis of dimethyl carbonate, its feature is being a kind of method by the synthetic dimethyl carbonate catalyst of methanol oxidation carbonylation, and adopting liquid-phase precipitation, crystallization and the method for washing main active constituent that makes that combines is the catalyst of γ-basic copper chloride.Concrete preparation process is with copper chloride and cupric oxide, NaOH or ammoniacal liquor reaction, generate the basic copper chloride crystallization gradually, its pH value scope is 7.0～10.0, and temperature is 40～80 ℃, adopt washing to purify then, obtain containing the catalyst of 60-95% γ-basic copper chloride.

The catalyst of Synthesis of dimethyl carbonate of the present invention has the following advantages: 1) corrosivity is little; 2) raw material is easy to get, low price, and preparation process is simple; 3) active good, the selectivity height, the life-span is long.

Four, the specific embodiment

Embodiment 1:

In glass beaker, add 500ml distilled water, under function composite by electromagnetic stirring, with 36 gram CuCl ₂2H ₂O slowly adds and is made into the aqueous solution, continues to stir also to be heated to 80 ℃, and 10 gram CuO are slowly added, and is stirred and heated to up to solvent all to evaporate and pasty mass occurs, and washing is at 80 ℃ of dry 24h.Get 28.2 gram catalyst, contain γ-basic copper chloride 95% approximately, be designated as sample a.

Embodiment 2:

In glass beaker, add 210ml distilled water, under function composite by electromagnetic stirring, with 13.77 gram CuCl ₂2H ₂O slowly adds and is made into the aqueous solution, at another beaker, 6.826 gram NaOH is dissolved into 30ml distilled water, and NaOH solution slowly is added drop-wise to CuCl ₂In the aqueous solution, adjusting ph value to 7 with the water-bath heating, is incubated half an hour, filters, and washing at 80 ℃ of dry 24h, gets catalyst 16.5 grams, contains γ-basic copper chloride 76% approximately, is designated as sample b.

Embodiment 3:

In glass beaker, add 500ml distilled water, under function composite by electromagnetic stirring, with 3 gram CuCl ₂2H ₂O slowly adds and is made into the aqueous solution, joins the NH that gets 12mol/ml ₃H ₂O slowly drips NH with pipette ₃H ₂O is to CuCl ₂In the aqueous solution, the pH value of control solution is 5～7, behind the reaction 18h, is adding thermal agitation, and up to pasty mass occurring, washing at 80 ℃ of dry 24h, gets catalyst 2.76 grams, contains γ-basic copper chloride 88% approximately, is designated as sample c.

Embodiment 4:

The watery hydrochloric acid that adds 300ml 3.52% in glass beaker under function composite by electromagnetic stirring, slowly adds 48 gram CuO, is stirred and heated to 80 ℃, up to pasty mass occurring, washing is at 80 ℃ of drying 2～24h, get catalyst 32.4 grams, contain γ-basic copper chloride 65% approximately, be designated as sample d.

Embodiment 5-8:

Select catalyst sample a for use, b carries out high pressure three phase slurry bed activity rating, and reaction condition is: T=120 ℃, and P=3.0MPa, t=4h, CO/O ₂=2; Select catalyst sample c for use, d carries out the continuous fixed bed activity rating of normal pressure, and reaction condition is: T=120 ℃, and P=0.1MPa, t=6h, CO/O ₂=11; Product is by gas-chromatography (PE8500 of U.S. PE company) thermal conductivity cell detector analysis, and except that DMC, main byproduct is dimethoxym ethane (DMM), and response data sees Table 1.

The methanol oxidation carbonylation catalytic reaction effect of the different samples of table 1

Claims

1. the catalyst of a Synthesis of dimethyl carbonate, it is characterized in that it being a kind of catalyst by the synthetic dimethyl carbonate of methanol oxidation carbonylation, this catalyst is main active constituent with γ-basic copper chloride, with copper chloride and NaOH or ammoniacal liquor reaction, control pH value of solution value scope is 7.0～10.0, temperature is 40～80 ℃, generate the basic copper chloride crystallization gradually, wash purification then, obtain containing the catalyst of 60～95% γ-basic copper chloride, the crystal structure of described γ-basic copper chloride is γ-Cu ₂(OH) ₃Cl, JCPDS card number are 25-1427, monoclinic form.

2. the Preparation of catalysts method of the described Synthesis of dimethyl carbonate of claim 1, it is characterized in that it being a kind of Preparation of catalysts method by the synthetic dimethyl carbonate of methanol oxidation carbonylation, adopt liquid-phase precipitation, crystallization and method for washing are the catalyst of main active constituent in conjunction with what make with γ-basic copper chloride, concrete preparation process is with copper chloride and NaOH or ammoniacal liquor reaction, generate the basic copper chloride crystallization gradually, the pH value scope of control solution is 7.0～10.0, temperature is 40～80 ℃, adopt washing to purify then, obtain containing the catalyst of 60-95% γ-basic copper chloride.