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Method for preparing anhydrous formaldehyde

A technology for anhydrous formaldehyde and methanol, which is applied in the direction of dehydrogenation preparation, carbon-based compound preparation, chemical instruments and methods, etc., and can solve the problems of many by-products and difficult regulation of catalyst acidity and alkalinity

Inactive Publication Date: 2020-06-02
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The significance of the present invention is to overcome the shortcomings of the catalysts currently used in the preparation of anhydrous formaldehyde, such as the difficulty in adjusting the acidity and alkalinity of the catalyst, and more by-products, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Preparation of (0.5wt%Pt-0.5wt%In) / SiO by Co-precipitation 2 Catalyst, the operation is as follows: Weigh 2g nano-SiO 2 (50nm), dispersed into 20mL of water, respectively added a certain amount of Na 2 PtCl 4 and InCl 3 4H 2 O, stirred for 1 h, and adjusted the pH value of the suspension to 11 with 30% ammonia water. Stir for 1 hour, centrifuge and wash until neutral, dry in an oven at 80°C, and dry at 500°C H 2 Reduction in medium for 2h, prepared (0.5wt%Pt-0.5wt%In) / SiO 2 catalyst. Weigh 2 g of the catalyst to form a tablet and fill it into a fixed-bed reactor. Under normal pressure, nitrogen gas is used as the carrier gas, methanol is injected by a parallel flow pump, the volume ratio of methanol is 10vol%, the feed rate of methanol is 0.30mL / (gcat. min), the reaction is at 400°C, and the conversion rate of methanol is detected by gas chromatography on-line. %, formaldehyde selectivity is 63%.

Embodiment 2

[0015] Preparation of (0.5wt%Pt-1.0wt%In) / SiO by Co-precipitation 2 Catalyst, the operation is as follows: Weigh 2g nano-SiO 2 (50nm), dispersed into 20mL of water, respectively added a certain amount of Na 2 PtCl 4 and InCl 3 4H 2 O, stirred for 1 h, and adjusted the pH value of the suspension to 11 with 30% ammonia water. Stir for 1 hour, centrifuge and wash until neutral, dry in an oven at 80°C, and dry at 450°C H 2 Reduction in medium for 2h, prepared (0.5wt%Pt-1.0wt%In) / SiO 2 catalyst. Weigh 2 g of the catalyst to form a tablet and fill it into a fixed-bed reactor. Under normal pressure, nitrogen gas is used as the carrier gas, methanol is injected by a parallel flow pump, the volume ratio of methanol is 15vol%, the feed rate of methanol is 0.25mL / (gcat. min), the reaction is at 450°C, and the conversion rate of methanol is 77% as detected by gas chromatography on-line. %, formaldehyde selectivity is 85%.

Embodiment 3

[0017] Preparation of (1.5wt%Pt-0.5wt%In) / SiO by Co-precipitation 2 Catalyst, the operation is as follows: Weigh 2g nano-SiO 2 (50nm), dispersed into 20mL of water, respectively added a certain amount of Na 2 PtCl 4 and InCl 3 4H 2 O, stirred for 1 h, and adjusted the pH value of the suspension to 11 with 30% ammonia water. Stir for 1 hour, centrifuge and wash until neutral, dry in an oven at 80°C, and dry at 500°C H 2 Reduction in medium for 2h, prepared (1.5wt%Pt-0.5wt%In) / SiO 2 catalyst. Weigh 2 g of the catalyst to form a tablet and fill it into a fixed-bed reactor. Under normal pressure, nitrogen gas is used as carrier gas, methanol is injected by a parallel flow pump, the volume ratio of methanol is 30vol%, the feed rate of methanol is 0.20mL / (gcat.min), the reaction is at 450°C, and the conversion rate of methanol is 68% by gas chromatography on-line detection %, formaldehyde selectivity is 75%.

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Abstract

The invention relates to a method for preparing anhydrous formaldehyde. According to the method, a silicon dioxide supported platinum-indium catalyst (PtIn / SiO2) is adopted; and the method specifically comprises the following steps: molding a PtIn / SiO2 catalyst, loading into a reaction tube, loading into a fixed bed reactor, and carrying out a reaction under normal pressure at a temperature of 400-650 DEG C, wherein methanol is injected through a constant-flux pump, inert gas serves as carrier gas, the methanol feeding ratio is 10-60 vol%, the methanol feeding speed is 0.10-0.30 mL / (gcat.min),and the chromatography determination results show that the methanol conversion rate is 65-90% and the formaldehyde selectivity is 60-85%. According to the method for preparing the anhydrous formaldehyde, PtIn / SiO2 is adopted as the catalyst, and has high catalytic activity and high product selectivity, few byproducts are produced, the preparation process of the catalyst is simple, and the thermalstability is high.

Description

technical field [0001] The invention relates to a method for preparing formaldehyde, in particular to a method for preparing anhydrous formaldehyde by dehydrogenating methanol. Background technique [0002] Formaldehyde is an important organic chemical raw material, which can be used to produce thermosetting resins such as phenolic resin and melamine resin, as well as bulk chemicals such as polyoxymethylene, phenolic aldehyde, urotropine, and 1,4-butanediol. Formaldehyde is also a synthetic dye , pesticides, disinfectants, adhesives and other important raw materials. [0003] At present, methanol oxidation is generally used in industry to prepare formaldehyde. In theory, formaldehyde aqueous solution with a molar ratio of 1:1 can be obtained, but the vapor pressure of formaldehyde aqueous solution is low, and formaldehyde and water form an azeotrope, so it is very difficult to separate and purify formaldehyde. High energy consumption. In recent years, there is an increasin...

Claims

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Application Information

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IPC IPC(8): B01J23/62C07C45/00C07C47/04
CPCB01J23/62C07C45/002C07C47/04
Inventor 王峰吕建民韩建宇
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI