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Application method of heteropoly acid type catalyst

A technology of heteropoly acid and catalyst, applied in chemical instruments and methods, physical/chemical process catalyst, chemical/physical process, etc., can solve the problem of unstable acid strength and achieve the effect of stabilizing catalytic performance

Inactive Publication Date: 2003-01-15
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

[0005] However, a disadvantage of heteropolyacids or heteropolyacid salts as solid acid catalysts is that their acidity, especially their acid strength, is unstable under common reaction conditions.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Example 1. Preparation of catalyst

[0024] Put 100 grams of SiO 2 Washed with dilute hydrochloric acid, soaked for 2 hours, then washed with deionized water until neutral, and roasted in a muffle furnace at 350°C for 4 hours. Weigh 60 grams of SiO that has undergone the above treatment 2 , under vacuum for 2 hours at room temperature; dissolve 15 grams of phosphotungstic acid in 75 grams of deionized water, drop into the carrier under vacuum conditions, and continue to treat the impregnated samples under vacuum conditions for 1 hour, and then place them in an oven at 120 °C. After drying, catalyst A was prepared.

Embodiment 2

[0025] Embodiment 2, catalyst acid strength determination method

[0026] The acid strength of the catalyst was determined by the Hammlett indicator method. A series of 0.1% Hammett indicator solutions were prepared. Take a small amount of catalyst sample and put it in a small test tube, drop the indicator solution, and observe whether it changes from basic color to acid color. When the heteropolyacid catalyst makes the indicator show acid color, it means that the acidity function Ho of the catalyst is less than or equal to the pK of the indicator a . pK by indicator a Measure in order from small to large, until the catalyst turns the indicator into an acid color, then the pK of the indicator a The value is the Ho value of the catalyst. The indicators used are listed in Table 1.

[0027] Table 1: Indicators used for acid strength determination

[0028] Indicator Base color Acid color pK a

[0029] Benzazonaphthylamine Yellow Red +4.0

[0030] Dimethyl Yellow Yellow R...

Embodiment 3

[0037] Example 3. Determination of catalyst under water pressure

[0038] Take 10 grams of catalyst A, put it into a glass reaction tube, put it in a tubular heating furnace, and make nitrogen gas with a flow rate of 40 ml / min bubble through in water at a certain temperature and flow through the reaction tube. Adjust the water temperature so that the partial pressure of the water vapor is 12.8 mmHg, heat up to 300 °C and then keep the temperature constant, take out a small amount of catalyst at regular intervals, and quickly measure its acid strength by the Hammett indicator method. The measurement results are shown in Table 2.

[0039] Table 2 Changes in acid strength of catalyst A under 12.8 mmHg water pressure

[0040] 300℃ constant temperature time / h Ho

[0041] 0 -11.35≤Ho≤-8.20

[0042] 1 -13.75≤Ho≤-12.70

[0043] 2 Ho≤-13.75

[0044] 4 Ho≤-13.75

[0045] 6 Ho≤-13.75

[0046]8 Ho≤-13.75

[0047] 19 Ho≤-13.75

[0...

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PUM

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Abstract

A process for improving the acid intensity stability of solid acid catalyst containing heteropoly acid or its salt (0.5-100 wt.%) features that said heteropoly acid or its salt has central atom (P or Si) and coordinating atom chosen from W, Mo and V, and there is water in reaction atmosphere.

Description

technical field [0001] The present invention relates to a method for using a heteropolyacid type catalyst. Background technique [0002] As a new class of catalytic materials, heteropolyacids and heteropolyacid salts have received extensive attention in the field of catalysis due to their unique acidity, "quasi-liquid phase" behavior, strong acidity and strong oxidizing properties at the same time. [0003] Chinese Patent Publication No. 1185992 discloses a composite catalyst of silica-supported phosphotungstic acid and magnesium nitrate for isobutylene production by ether cracking. The conversion rate of methyl tert-butyl ether and the selectivity of isobutylene are both greater than 99%. [0004] USP 5,750,457 discloses a Cs loaded with precious metal Pd 2.5 H 0.5 PW 12 O 40 The catalyst is used in the n-butane isomerization reaction under hydrogen conditions, and the good results of n-butane conversion rate of 33.6% and isobutane selectivity of 95.5% can be obtained. ...

Claims

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Application Information

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IPC IPC(8): B01J27/199
Inventor 王清遐刘晓萍何盛宝徐龙伢孙新德
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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