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Preparation of hydrogenated pyromellitic acid ester

A technology for hydrogenating pyromellitic acid esters and pyromellitic acid, which is applied in the preparation of organic compounds, carboxylate esters, organic chemistry, etc., can solve the problems of rapid catalyst deactivation, frequent regeneration, and short service life. Achieve the effects of improving anti-sintering ability, improving dispersion and high selectivity

Active Publication Date: 2012-03-21
威海新元科盛新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This invention solves the shortcomings of the existing technology of directly using pyromellitic acid as raw material to hydrogenate hydrogenated pyromellitic acid to prepare hydrogenated pyromellitic acid, such as rapid catalyst deactivation, short service life, and frequent regeneration during use. Aluminum oxide is used as a carrier to prepare a large-pore carrier, which provides a favorable reaction environment for the hydrogenation of large-sized reactant molecules. The anti-sintering ability of precious metal element microcrystals under hydrogen reaction conditions provides catalysts with longer hydrogenation service life

Method used

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  • Preparation of hydrogenated pyromellitic acid ester
  • Preparation of hydrogenated pyromellitic acid ester
  • Preparation of hydrogenated pyromellitic acid ester

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Mix commercially available pseudo-boehmite and aluminum hydroxide powder in a certain proportion to form a uniform powder, weigh quantitative dilute nitric acid and phosphoric acid to prepare an aqueous solution, and spray the prepared solution evenly on the powder in a kneader , and then spray quantitative polyethylene glycol aqueous solution evenly in the mixture, after aging for a certain period of time, extrude on a twin-screw extruder, dry and roast under preset program temperature control to obtain strip-shaped composite alumina , crushed and sieved to take a certain particle size carrier to obtain the composite catalyst carrier used in the present invention. Prepare the following 1-7 carriers according to different raw material ratios:

[0030] Table 1 Preparation and characterization of composite alumina carrier

[0031]

Embodiment 2

[0033] Weigh 100g of carriers 1 to 7 in Example 1, respectively put them into 100ml (0.012g Sr / ml) of strontium nitrate aqueous solution for immersion for 24 hours, dry at 120°C for 12 hours, and then roast at 400°C for 3 hours to obtain rare earth modified Composite alumina carrier.

[0034] Put the above-mentioned pretreated carriers into 125ml of mixed aqueous solution containing ruthenium chloride and rhodium chloride respectively, wherein the Ru content is 0.002g / m1, and the Rh content is 0.0004g / ml, after soaking for 24 hours, dry at 120°C for 6 hours, repeat The above operations were performed 4 times, and after drying, they were calcined at 400°C for 4 hours to obtain the corresponding catalysts H-1, H-2, H-3, H-4, H-5, H-6, and H-7, loaded with 1% Ru and 0.2% Rh.

Embodiment 3

[0036] Tetrabutyl pyromellitic acid was dissolved in butanol to form a butanol solution containing 23% (wt) tetrabutyl pyromellitic acid, which was used as a reaction raw material solution. Load the catalyst in a single-tube fixed-bed reactor, reduce and activate it under a hydrogen atmosphere at a programmed temperature rise, and feed the raw material solution into the reactor through a metering pump for hydrogenation reaction. Reaction conditions: pressure 6.0Mpa, bed temperature 220 ℃, liquid space velocity 4.0h 1(V), hydrogen air velocity 250h 1 (V), after the hydrogenation mixed product is cooled, obtain the mixed product of the hydrogenated tetrabutylpyromellitic acid containing solvent butanol, carry out chromatographic analysis, as follows:

[0037] Table 2 Catalyst Activity Evaluation

[0038] catalyst Conversion rates(%) selectivity (%) H-1 99.6 98.4 H-2 99.1 98.0 H-3 99.4 98.2 H-4 99.0 9.6 H-5 ...

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Abstract

In the invention, a catalyst used for hydrogenation reaction of pyromellitic acid ester to prepare hydrogenated pyromellitic acid ester is prepared, the catalyst is prepared by loading multi-component noble metal on a rare-earth modified and compounded aluminum oxide carrier, and the hydrogenation catalyst has high activity, high selectivity and long life.

Description

technical field [0001] The invention relates to the preparation and use of a catalyst for preparing hydrogenated pyromellitic acid esters. The hydrogenated pyromellitic acid esters are prepared by hydrogenation reaction of pyromellitic acid esters. Under certain temperature, hydrogen pressure and catalyst action, the After the benzene ring in the pyromellitic acid ester molecule is subjected to saturated hydrogenation, an alicyclic tetrabasic ester is obtained, which is used as a fine chemical intermediate to prepare hydrogenated pyromellitic dianhydride. The catalyst prepared in the invention is suitable for the catalytic hydrogenation process of pyromellitic acid esters, and has the characteristics of high activity and high selectivity. Background technique [0002] Hydrogenated pyromellitic dianhydride (HPMDA) is a new type of alicyclic anhydride used to prepare hydrogenated pyromellitic dianhydride polyimide (PI). Since HPMDA does not contain aromatic components in its ...

Claims

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Application Information

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IPC IPC(8): C07C69/75C07C67/303B01J27/18
Inventor 李璐王超杨丰华
Owner 威海新元科盛新材料有限公司
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