CN109647465B

CN109647465B - Catalyst for synthesizing partial anhydride

Info

Publication number: CN109647465B
Application number: CN201710946329.0A
Authority: CN
Inventors: 徐俊峰; 顾龙勤; 金照生
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2017-10-12
Filing date: 2017-10-12
Publication date: 2020-10-16
Anticipated expiration: 2037-10-12
Also published as: CN109647465A

Abstract

The invention relates to a catalyst for synthesizing meta-anhydride, which mainly solves the problem that the reaction for preparing the meta-anhydride by oxidizing meta-trimethylbenzene in the prior art generates a plurality of byproducts, so that the yield of the meta-anhydride is low. The invention adopts the technical scheme that the vanadium oxide supported catalyst comprises the active component of at least one of vanadium element, titanium element, alkaline earth metal element and III B group element, thereby better solving the technical problem, improving the selectivity of the catalyst to the meta-anhydride, reducing the generation of byproducts and effectively improving the yield of the meta-anhydride.

Description

Catalyst for synthesizing partial anhydride

Technical Field

The invention relates to a catalyst for synthesizing a meta-anhydride, a preparation method thereof and a synthesis method of the meta-anhydride.

Technical Field

Trimellitic anhydride (TMA), also known as 1, 2, 4-benzene tricarboxylic anhydride for short, is an important chemical raw material and a high value-added intermediate, and is widely applied to the production industries of high-temperature-resistant plasticizers, polyester resins, polyester epoxy powder coatings, insulating paint, water-soluble alkyd resins, lubricating oil, printing ink, adhesives and the like. The prepared resin material has excellent point insulation performance, high temperature resistance and mechanical performance, and is widely applied to the industrial fields of electronics, aerospace, electromechanics and the like.

At present, the production of the meta-anhydride in the world is mainly based on the pseudocumene liquid-phase oxidation technology represented by the United states and Japan, and accounts for about 70 percent of the total production in the world. The process takes pseudocumene as a raw material, takes Co-Mn-Br as a catalyst in an acetic acid medium, and prepares the meta-anhydride by air oxidation. The process has high yield of the meta-anhydride, but has long reaction flow, serious corrosion to equipment and large investment, and can bring pressure to the production cost. The gas phase oxidation method is a method for directly generating the meta-anhydride by using the air to carry out one-step oxidation by using the pseudocumene as a raw material under the action of a catalyst. Compared with the liquid phase oxidation method, the method avoids the problems, has low production cost and is the most ideal method for producing the meta-anhydride.

At present, the gas phase oxidation method causes high international attention, and research work of the method is developed in many times. German GE1518613 researches V-Mo-Cu catalyst for gas phase oxidation of pseudocumene, and obtains good catalytic effect. JP48-49736 studies a V-Ti catalyst for the catalytic oxidation of mesitylene with an oxygen-containing gas. CN 105498817A researches a V-Ti-Mn-Co metal oxide and heteropoly acid composite catalyst, and the molar yield can reach 56.2%. Compared with the prior art at home and abroad, the prior art at home is still imperfect, has low construction rate and can not meet the market demand of the domestic meta-anhydride. Therefore, it is necessary to improve the selectivity of the catalyst to the partial anhydride by changing the preparation method of the catalyst.

Disclosure of Invention

One of the technical problems to be solved by the invention is the problem of low yield of the meta-anhydride in the prior art, and the invention provides a catalyst for preparing the meta-anhydride, which has the characteristic of high yield of the meta-anhydride.

The second technical problem to be solved by the present invention is to provide a method for preparing a catalyst corresponding to the first technical problem.

The present invention is also directed to a method for preparing a meta-anhydride, which is one of the technical problems to be solved.

In order to solve one of the above technical problems, the technical solution disclosed by the present invention is: the catalyst for synthesizing the meta-anhydride is characterized in that the catalyst is a supported catalyst, and the active component of the supported catalyst comprises vanadium element, titanium element and at least one of alkaline earth metal element and IIIB group element; the carrier of the catalyst is inert silicon carbide, alpha-alumina or ceramic ring.

Preferably, the active component includes both vanadium element, titanium element, at least one element selected from alkaline earth metal elements, and at least one element selected from group iiib elements. At the moment, the alkaline earth metal element and the IIIB group element have synergistic effect on the aspect of improving the yield of the partial anhydride.

In the above technical solution, the alkaline earth metal element is at least one selected from Be, Mg, Ca, Sr and Ba. More preferably Mg and Ba.

In the above technical solution, the group iiib element is at least one selected from Sc and Y.

In the above technical solutions, as the most preferable technical solution, the active component simultaneously includes a vanadium element, a titanium element, an alkali metal element, and a nonmetal element; for example, the active components include V, Ti, Mg and Sc, or V, Ti, Mg, Ba and Sc, or V, Ti, Mg, Sc and Y, or V, Ti, Mg, Ba, Sc and Y.

In the technical scheme, the molar ratio of the vanadium element to the titanium element in the catalyst is 1: (1-15), more preferably 1: (5-10);

the molar ratio of vanadium element to the sum of alkaline earth metal element and IIIB group element in the catalyst is 1: (0.01-0.8), more preferably 1: (0.05-0.8).

The technical scheme is characterized in that the molar ratio of the active component to the carrier in the supported catalyst is 1 (1-10).

To solve the second technical problem, the technical solution of the present invention is as follows: the preparation method for the catalyst for synthesizing the partial anhydride, which is described in the technical scheme of one of the technical problems, comprises the following steps:

(1) dissolving oxalic acid in distilled water to obtain an oxalic acid solution; adding a vanadium source into an oxalic acid solution to obtain a mixed solution; dissolving alkaline earth metal elements and IIIB group element compounds by using distilled water, and adding the mixture into a reaction system;

(2) adding water into a titanium source, grinding, slowly dropwise adding the ground titanium source into a reaction system, and fully stirring to prepare slurry to obtain a precursor;

(3) spraying the precursor on a carrier, and roasting to obtain the catalyst.

In the above technical solution, the vanadium source in step (1) is preferably at least one selected from vanadium oxide, metavanadate, orthovanadate and vanadium chloride. The titanium source in the step (2) is preferably at least one of titanium dioxide and titanium tetrachloride. The compound of the alkaline earth metal element in the step (1) is preferably at least one selected from salts such as magnesium nitrate, magnesium sulfate, magnesium acetate, barium nitrate, barium sulfate, and barium acetate. More preferred are magnesium acetate and barium nitrate.

The compound of a group IIIB element in the step (1) is preferably at least one selected from the group consisting of scandium halides, scandium sulfates, yttrium halides and yttrium sulfates. Scandium chloride and yttrium chloride are more preferred.

In the technical scheme, the preparation method for preparing the metaanhydride catalyst is characterized in that a precursor of the catalyst is put into a spraying machine, heated at 120-400 ℃ and uniformly sprayed on a carrier.

In the technical scheme, the preparation method for the catalyst for preparing the metaanhydride is characterized in that the carrier sprayed with the catalyst precursor is roasted in a muffle furnace, the roasting temperature is 350-650 ℃, and the roasting time is 1-15 h.

To solve the third technical problem, the technical scheme of the invention is as follows: the method for preparing the meta-anhydride takes durene, water vapor and air as raw materials and adopts a fixed bed reactor to synthesize the meta-anhydride in the presence of a catalyst.

The reaction process conditions in the technical scheme are as follows: the volume ratio of the pseudocumene to the steam is 1: 1-35, and the reaction process conditions are as follows: the airspeed is 1050-10000 hr^-1The reaction temperature is 300-650 ℃, and the reaction pressure is normal pressure.

Compared with the prior art, the key point of the invention is that the active component of the catalyst comprises a certain amount of vanadium element, titanium element and at least one element selected from alkaline earth metal elements and III B group elements, which is beneficial to improving the performance of the catalyst, thereby improving the yield of the meta-anhydride.

The experimental result shows that the mole yield of the meta-anhydride prepared by the invention reaches 63.2%, and the good technical effect is achieved, especially when the active component in the catalyst simultaneously comprises vanadium element, titanium element, at least one element selected from alkaline earth metal elements and at least one element selected from IIIB group elements, the more outstanding technical effect is achieved, and the method can be used for the synthesis of the meta-anhydride. The invention is further illustrated by the following examples.

Detailed Description

[ example 1 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirringAnd obtaining the ammonium vanadyl oxalate solution. 0.4 molar parts of magnesium acetate is dissolved by 48ml of distilled water and then added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.6% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 2 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.4 molar part of scandium chloride was dissolved in 48ml of distilled water and added to the solution, and the reaction was continued at 60 ℃ for 1 hour. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.4% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

Comparative example 1

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, continuously stirring to obtain an ammonium vanadyl oxalate solution, and continuously reacting for 1h at 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. In muffle furnaceRoasting at 520 ℃ and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is determined to be 59.8% by evaluation in a fixed bed reactor, the evaluation results are detailed in table 1.

Compared with the examples 1-2, the catalyst adopted by the invention has better performance and higher yield of the anhydride compared with the catalyst only containing V, Ti active components, wherein the catalyst contains V, Ti and Mg active components and V, Ti and Sc active components.

[ example 3 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. And adding 1 mol part of ammonium metavanadate into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.4 molar part of barium acetate is dissolved by 48ml of distilled water and then added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 20ml of distilled water into 5 molar parts of titanium dioxide, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.3% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 4 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.4 molar part of magnesium nitrate is dissolved in 48ml of distilled water and added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. In muffle furnacesRoasting at 520 ℃, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.5% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 5 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. And adding 1 mol part of ammonium metavanadate into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. After 0.4 molar part of barium nitrate is dissolved by 48ml of distilled water, the solution is added, and the reaction is continued for 1 hour at 60 ℃. Adding 20ml of distilled water into 5 molar parts of titanium dioxide, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.4% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 6 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.4 molar part of scandium sulfate was dissolved in 48ml of distilled water, and then added to the solution, and the reaction was continued at 60 ℃ for 1 hour. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.3% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 7 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. And adding 1 mol part of ammonium metavanadate into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.4 molar part of yttrium sulfate is dissolved by 48ml of distilled water and then added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 20ml of distilled water into 5 molar parts of titanium dioxide, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.4% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 8 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. And adding 1 mol part of ammonium metavanadate into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.4 molar part of yttrium chloride is dissolved by 48ml of distilled water and then added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 20ml of distilled water into 5 molar parts of titanium dioxide, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the meta-anhydride is 63.6% by evaluation in a fixed bed reactor, the evaluation results are shown in table 1.

[ example 9 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. By distillation of 48mlDissolving 0.2 molar parts of magnesium acetate and 0.2 molar parts of scandium chloride in water, adding the solution into the solution, and continuously reacting for 1 hour at the temperature of 60 ℃. Adding 5 parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the yield of the anhydride is measured in a fixed bed reactor, the yield of the anhydride is 64.0 percent, and the evaluation result is detailed in table 1.

Compared with the examples 1-2, the alkaline earth metal Mg element and the IIIB group Sc element have better synergistic effect on improving the yield of the partial anhydride.

[ example 10 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. Dissolving 0.1 molar part of magnesium acetate, 0.1 molar part of calcium sulfate and 0.2 molar part of scandium chloride in 48ml of distilled water, adding the solution into the solution, and continuously reacting for 1 hour at the temperature of 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the metaanhydride is measured to be 64.6 percent by evaluation in a fixed bed reactor, the evaluation result is detailed in table 1.

Compared with example 9, it can be seen that the alkaline earth metals Mg and Ba have better synergistic effect with other active components of the invention in increasing the yield of the partial anhydride.

[ example 11 ]

Weighing 55g of oxalic acid and 180ml of distilled water in a flask, stirring and heating to 85 ℃, and waiting for the oxalic acid to be completely dissolvedThen, oxalic acid solution is prepared. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.2 molar parts of magnesium acetate, 0.1 molar parts of scandium chloride and 0.1 molar parts of yttrium chloride are dissolved by 48ml of distilled water and then added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the metaanhydride is 64.4% by evaluation in a fixed bed reactor, the evaluation results are detailed in table 1.

In this example, it can be seen that compared to example 5, group IIIB Sc and Y elements have a better synergistic effect with other active ingredients of the present invention in increasing the yield of the partial anhydride.

[ example 12 ]

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. 0.2 mole parts of barium acetate, 0.1 mole parts of scandium chloride and 0.1 mole parts of yttrium chloride are dissolved by 48ml of distilled water and then added into the solution, and the reaction is continued for 1 hour at 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the metaanhydride is measured to be 64.5 percent by evaluation in a fixed bed reactor, the evaluation result is detailed in table 1.

[ example 13 ]

Weighing 55g of oxalic acid and 180ml of distilled water in a flask, stirring and heating to 85 ℃ until oxalic acid is obtainedAfter all the components are dissolved, oxalic acid solution is prepared. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. Dissolving 0.1 molar part of magnesium acetate, 0.1 molar part of calcium sulfate, 0.1 molar part of scandium chloride and 0.1 molar part of yttrium chloride by using 48ml of distilled water, adding the solution into the solution, and continuously reacting for 1 hour at the temperature of 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the metaanhydride is 65.3 percent, the evaluation result is detailed in table 1.

Comparing this example with examples 10 and 11, it can be seen that V, Ti, the alkaline earth metals Mg and Ba, and the IIIB group Sc and Y have very good synergistic effect in increasing the yield of the partial anhydride.

Comparative example 2

55g of oxalic acid and 180ml of distilled water are weighed in a flask, stirred and heated to 85 ℃, and the oxalic acid solution is prepared after the oxalic acid is completely dissolved. Adding 1 mol part of vanadium pentoxide into the prepared oxalic acid solution, and continuously stirring to obtain the ammonium vanadyl oxalate solution. Dissolving 0.2 mole parts of manganese nitrate and 0.2 mole parts of cobalt nitrate in 48ml of distilled water, adding the solution, and continuously reacting for 1 hour at the temperature of 60 ℃. Adding 5 molar parts of titanium tetrachloride into 20ml of distilled water, grinding, adding into a reaction system, and fully stirring to prepare slurry to obtain a precursor. The catalyst precursor is loaded into a spraying machine and evenly sprayed on the inert carrier silicon carbide. Roasting at 520 ℃ in a muffle furnace, and naturally cooling to obtain the catalyst. The catalyst is reacted at the temperature of 400 ℃ and the space velocity of 3400h^-1The following, pseudocumene: when the steam is 0.05 and the mole yield of the metaanhydride is measured to be 62.9 percent when the evaluation is carried out in a fixed bed reactor, the evaluation result is detailed in the table 1.

TABLE 1

Claims

1. A method for synthesizing the meta anhydride, take meta-trimethyl benzene, water vapor, air as raw materials, adopt the fixed bed reactor, synthesize the meta anhydride and synthesize the meta anhydride under the existence of catalyst; the catalyst is a supported catalyst, and the active components of the supported catalyst comprise vanadium element, titanium element and IIIB group element, or vanadium element, titanium element, IIIB group element and alkaline earth metal element; the carrier of the catalyst is inert silicon carbide, alpha-alumina or ceramic ring;

the IIIB group element is selected from at least one of Sc and Y; the molar ratio of the vanadium element to the titanium element in the catalyst is 1: (1-15); the molar ratio of vanadium element to the sum of alkaline earth metal element and IIIB group element in the catalyst is 1: (0.01-0.8).

2. The method according to claim 1, wherein the alkaline earth metal element is at least one selected from Be, Mg, Ca, Sr and Ba.

3. The process of claim 1, wherein the molar ratio of active component to support in the supported catalyst is from 1 (1) to 10.

4. A process according to any one of claims 1 to 3, wherein the catalyst is prepared by a process comprising the steps of:

(3) spraying the precursor on a carrier, and roasting to obtain the catalyst.

5. The method of claim 4, wherein the precursor of the catalyst is charged into a spray coater and heated at 120-400 ℃ to uniformly spray the precursor onto the support.

6. The method of claim 4, wherein the support coated with the catalyst precursor is calcined in a muffle furnace at a temperature of 350-650 ℃ for a time of 1-15 hours.

7. The process of claim 1, wherein the volumetric ratio of mesitylene to steam fed is 1: 1-35, and the reaction process conditions are as follows: the airspeed is 1050-10000 hr^-1The reaction temperature is 300-650 ℃, and the reaction pressure is normal pressure.