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Method for preparing polyoxymethylene dimethyl ethers

A technology of polyoxymethylene dimethyl ether and dimethyl ether, which is applied in chemical instruments and methods, preparation of organic compounds, metal/metal oxide/metal hydroxide catalysts, etc., and can solve problems such as unsatisfactory selectivity

Active Publication Date: 2015-07-15
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] So far, a variety of methods for preparing PODE have been reported, such as US.Pat.No.6,166,266 discloses a continuous method for preparing PODE, which involves the preparation of PODE by the condensation reaction of formaldehyde and dimethyl ether, the condensation catalyst used is silicon Acid salts (such as borosilicate or aluminum silicate) molecular sieves, thus, lead to products (especially PODE n＞2 ) selectivity is not ideal

Method used

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  • Method for preparing polyoxymethylene dimethyl ethers
  • Method for preparing polyoxymethylene dimethyl ethers
  • Method for preparing polyoxymethylene dimethyl ethers

Examples

Experimental program
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preparation example Construction

[0012] (1) Carrier (γ-Al 2 o 3 ) preparation:

[0013] Prepare aluminum sulfate in water at 60°C to 70°C to make an aqueous solution with a relative density of 1.21 to 1.23, and at the same time prepare Na with a mass percentage of 20%. 2 CO 3 aqueous solution;

[0014] Under the condition of 50 ℃ ~ 60 ℃, the aluminum sulfate aqueous solution with a relative density of 1.21 ~ 1.23 and 20% by mass percent of Na 2 CO 3 The aqueous solution is mixed, there is precipitation, filter, and the filter cake is washed with distilled water at a temperature of 50 ° C to 60 ° C until the washing liquid does not contain SO 4 2- ions (can pass Ba 2+ detection);

[0015] Put the washed filter cake in ammonia water with a temperature of 50°C-60°C and a pH value of 9.0-11.0, let it stand for at least 4 hours (curing), filter, and use distilled water at a temperature of 50°C-60°C again for the filter cake Wash until the specific resistance of the washing liquid is greater than 200 Ω / cm,...

Embodiment 1

[0024] Carrier (γ-Al 2 o 3 ) preparation:

[0025] Prepare aluminum sulfate in water at 60°C to 70°C to make an aqueous solution with a relative density of 1.21 to 1.23, and at the same time prepare Na with a mass percentage of 20%. 2 CO 3 aqueous solution;

[0026] Under the condition of 50 ℃ ~ 60 ℃, the aluminum sulfate aqueous solution with a relative density of 1.21 ~ 1.23 and 20% by mass percent of Na 2 CO 3 The aqueous solution is mixed, there is precipitation, filter, and the filter cake is washed with distilled water at a temperature of 50 ° C to 60 ° C until the washing liquid does not contain SO 4 2- ions (can pass Ba 2+ detection);

[0027] Put the washed filter cake in ammonia water with a temperature of 50°C-60°C and a pH value of 9.0-11.0, let it stand for at least 4 hours (curing), filter, and use distilled water at a temperature of 50°C-60°C again for the filter cake Wash until the specific resistance of the washing liquid is greater than 200Ω / cm, and ...

Embodiment 2

[0029] Take by weighing 20 grams of gamma-Al that is made by embodiment 1 2 o 3 , impregnated into a mixture consisting of 50 (mass)% ammonium molybdate, 10 (mass)% cobalt nitrate and 5 (mass)% niobium oxalate solution, and added citric acid to prevent precipitation. The immersion temperature is 70°C, the immersion time is 6 hours, then dried at 120°C for 12 hours, and finally roasted in air at 500°C for 6 hours to obtain the target catalyst (abbreviated as catalyst A): wherein metal molybdenum and / or its oxidation The content of metal cobalt and / or its oxide is 2.7wt%, the content of metal niobium and / or its oxide is 2wt%, and the balance is carrier (γ-Al 2 o 3 ).

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Abstract

The invention relates to a method for preparing polyoxymethylene dimethyl ethers from formaldehyde and dimethyl ether. The method comprises the following step that: in exist of a catalyst, methanol is reacted with formaldehyde formaldehyde to obtain the polyoxymethylene dimethylethers. The method is characterized in that: the catalyst is a supported catalyst, wherein an active component of the supported catalyst comprises: metallic molybdenum and / or its oxide, metallic iron and / or its oxide, and / or metallic niobium and / or its oxide, and a carrier of the supported catalyst is gamma-Al2O3 By the method, the selectivity of polyoxymethylene dimethylethers (CH3O(CH2O)xCH3, 3<=x<=4) can be raised 10-30%.

Description

technical field [0001] The invention relates to a method for preparing polyoxymethylene dimethyl ethers (Polyoxymethylene Dimethyl Ethers, PODE for short), in particular to a method for preparing polyoxymethylene dimethyl ethers by reacting formaldehyde and dimethyl ether. Background technique [0002] Polyoxymethylene dimethyl ether (PODE) is an oil additive with an average cetane number (CN) value of 76 and a high oxygen content. PODE can increase the calorific value of diesel and reduce exhaust emissions. Therefore, the preparation of PODE has attracted the attention of scientists. [0003] So far, a variety of methods for preparing PODE have been reported, such as US.Pat.No.6,166,266 discloses a continuous method for preparing PODE, which involves the preparation of PODE by the condensation reaction of formaldehyde and dimethyl ether, the condensation catalyst used is silicon Acid salts (such as borosilicate or aluminum silicate) molecular sieves, thus, lead to product...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C43/30C07C41/56B01J23/887
CPCB01J23/002B01J23/8877B01J2523/00C07C41/56C07C43/30B01J2523/68B01J2523/845B01J2523/56B01J2523/31
Inventor 刘殿华房鼎业张建强唐斌
Owner EAST CHINA UNIV OF SCI & TECH