阅读说明：本技术 一种具有可见光催化n2o参与选择性氧化的钌杂化十聚钨酸季铵盐的制备方法 (Visible light catalysis N has2Preparation method of ruthenium hybrid deca-poly quaternary ammonium tungstate with O participating in selective oxidation ) 是由 伏再辉 陈梦柯 张超 于 2019-09-20 设计创作，主要内容包括：本发明属于光催化材料制备与光催化氧化合成领域,具体公开了一种钌杂化十聚钨酸季铵盐催化剂的制备及可见光催化笑气(N_2O)参与选择氧化的方法。催化剂制备以二水合钨酸钠为原料,以三氯化钌(Ru~(III)Cl_3)、二氯化五氨合氯钌(III)(Ru~(III)(NH_3)_5Cl_2)、氯化三(2,2’-联吡啶)钌(II)六水合物(Ru~(II)(bpy)_3Cl_(2·)6H_2O)为杂化剂,通过酸化聚合、四烷基季铵阳离子交换和水热处理合成了一系列钌杂化十聚钨酸季铵盐催化剂。以乙腈为溶剂,酸性水溶液为促进剂,在常温常压和可见光照射下,该类催化剂能有效活化N_2O氧化环己烷、甲苯、乙苯、苯甲醇合成相应的含氧产物。(The invention belongs to the field of preparation of photocatalytic materials and photocatalytic oxidation synthesis, and particularly discloses preparation of a ruthenium hybrid deca-poly quaternary ammonium tungstate catalyst and visible light catalytic laughing gas (N) 2 O) a process involving selective oxidation. The catalyst is prepared by taking sodium tungstate dihydrate as a raw material and ruthenium trichloride (Ru) III Cl 3 ) Pentaammine ruthenium (III) chloride dichloride (Ru) III (NH 3 ) 5 Cl 2 ) Tris (2, 2' -bipyridine) ruthenium (II) chloride hexahydrate (Ru) II (bpy) 3 Cl 2· 6H 2 O) is a hybridization agent, and a series of ruthenium hybridization deca-poly ammonium tungstate catalysts are synthesized through acidification polymerization, tetraalkyl quaternary ammonium cation exchange and hydrothermal treatment. The catalyst can effectively activate N under the irradiation of visible light at normal temperature and pressure by taking acetonitrile as a solvent and an acidic aqueous solution as an accelerant 2 Oxidizing cyclohexane, toluene, ethylbenzene and benzyl alcohol by O to synthesize corresponding oxygen-containing products.)

1. Visible light catalysis N has₂The preparation method of the ruthenium hybridized deca-poly ammonium tungstate with O participating in selective oxidation is characterized by comprising the following steps of:

(1) weighing sodium tungstate dihydrate and divalent or trivalent ruthenium compound as dopant, dissolving in water to obtain mixed solution, boiling, adjusting pH to 2 with hydrochloric acid, and adjusting pH to 100^oPerforming acidification polymerization for 10min under C;

(2) adding excessive tetraalkylammonium salt solution into the polymerization liquid obtained in the step (1), and stirring at 80-100 ℃ under magnetic force^oC, carrying out cation exchange reaction for 25-35 min, and continuously separating out solids in the process;

(3) transferring the solid solution obtained in the step (2) into a polytetrafluoroethylene reaction kettle, carrying out hydrothermal treatment at a certain temperature for a period of time, then fully washing the cooled and filtered solid with water and ethanol, and 60^oAnd C, drying in vacuum for 12h to obtain the target catalyst ruthenium hybrid deca-poly-ammonium tungstate.

2. The method according to claim 1, wherein the trivalent or divalent ruthenium compound used as a dopant in step (1) is one of ruthenium (III) chloride, pentaammine ruthenium (III) chloride dichloride and tris (2, 2' -bipyridine) ruthenium (II) chloride hexahydrate, and the doping amount is 0 to 1.5 mol% based on the molar amount of ruthenium and decapolytungstate.

3. The method according to claim 1, wherein the tetraalkylammonium salt used in step (2) as a cation exchanger is tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide or tetrabutylammonium bromide in an amount of 2 to 3 times by mole the decatungstate groups.

4. The method according to claim 1, wherein the hydrothermal treatment temperature in the step (3) is 80-120 ℃ and the reaction time is 6-24 hours.

5. Visible light catalysis N₂The method for the selective oxidation of O comprises the step of N under the action of a catalyst and the irradiation of visible light₂O is used as an oxygen supply body for oxidizing various organic matters to synthesize corresponding oxygen-containing compounds, and is characterized in that the catalyst is the ruthenium compound hybrid deca-poly quaternary ammonium tungstate as claimed in claims 1-4, cyclohexane, benzyl alcohol, toluene and ethylbenzene are used as reaction substrates, acetonitrile is used as a solvent, water and an acidic aqueous solution are used as additives, a 15-60W halogen tungsten lamp is used as a light source, a photoreactor with a built-in light source is used, and magnetic stirring is carried out for 15-35^oAnd C, continuously carrying out illumination reaction for 6-14 h.

6. The process according to claim 5, characterized in that the catalyst is used in a molar amount of 0.8 to 1.5 mmol% based on the molar amount of the reaction substrate.

7. The method of claim 5, wherein the additive water is present in an amount of 0 to 0.2 mL.

8. The method according to claim 5, wherein the acid solution is one of hydrochloric acid, sulfuric acid, phosphoric acid, and benzenesulfonic acid, and has a mass concentration of 70% and is used in an amount of 1 to 5 times by mole the amount of the substrate.

Technical Field

The invention belongs to the field of photocatalytic material preparation and photocatalytic oxidation synthesis, and particularly discloses activated laughing gas (N)₂O) ruthenium hybrid decatungstate ammonium salt.

Background

Nitrous oxide (N)₂O) is commonly known as "laughing gas", a potent greenhouse gas that can destroy the atmospheric ozone layer, and is derived mainly from human activities and industrial production of nitric acid and adipic acid. In addition, due to its high oxygen content (36%) and the by-production of only green N₂ [ACS Catal. 2012, 2(4): 512-520]It is attractive as a highly selective oxygen atom donor in catalytic oxidation processes. However, N₂Chemical activation of O remains a major challenge in synthetic chemistry because of its kinetic inertness and its weak coordination capacity for transition metals. So far, N is under mild conditions₂The reaction involving O is still subject to considerable limitations since it is only possible to react with the very active Grignard reagent, N-heterocyclic carbene [ J. Am. chem. Soc. 2013,135(25): 9486-9492]，R₃P/Al(C₆F₅)₃Lewis acid-base pairs [ J. Am. chem. Soc.2013, 135(17): 6446-6449]Transition Metal Compound [ Chem Inform, 2010.41 (13)]And the like. Heterogeneous catalysts have been successfully used for N₂Selective oxidation of O, but high temperatures are generally required to effectively activate inert N₂And O. Homogeneous catalysts such as polyoxometallates and ruthenium complexes may also be used to catalyze N₂O-participated selective oxidation, but even with higher reaction temperatures (100-^oC) And the pressure, their catalytic efficiency (conversion number less than 100) is still not high [ Angew. chem. int. Ed. 2003, 42(1): 92-95]. It can be seen that N is difficult to achieve under mild conditions by chemical catalytic activation alone₂And selective oxidation with O.

Photoactivation of reactants and catalysts can generally be achieved under very mild conditions, and this activation technique has been widely used in the synthesis of fine chemicals. For example, tetrabutyl quaternary ammonium decatungstate (TBADT) has been widely used for photocatalytic O₂Participating in the selective oxidation of various organic compounds [ chem. Soc. Rev. 2009, 38(9): 2609-2621]. Based on high photocatalytic oxidation activity of TBADT and activated N of some ruthenium complexes₂O capacity, we suggest that if these two compounds can be effectively combined to form a new hybrid catalyst, it is likely that the hybrid catalyst can photoactivate N under mild conditions₂O participates in the selective oxidation reaction. This photocatalytically activates N₂The oxidation of cyclohexane by O to cyclohexanone and cyclohexanol (commonly known as KA oil) is of particular economic and environmental interest for the following reasons: KA oils are key intermediates for the production of synthetic fibers and fine chemicals [ J.chem. Educ. 1990, 67(3): A83]Its industrial production process is mainly cyclohexane oxidation process, but requires very severe reaction conditions such as high temperature (~ -.& Technol. 2012, 35(7): 1184-1204]. The newly designed photocatalytic process can overcome the above-mentioned problems in the commercial production of KA oil. On the other hand, the synthesis of adipic acid based on nitric acid oxidation of KA oil is still the dominant industrial production method, and the method is to effectively utilize a large amount of byproduct N₂O and the raw material circulation for producing adipic acid, and catalyzing N by Fe-ZSM-5₂The hydroxylation of benzene to phenol by O-oxidation has been developed to achieve this goal, but the process still has the disadvantages of harsh reaction conditions, high energy consumption and catalyst deactivation [ J. Catal. 2008, 260(1): 193-](ii) a And the conversion of phenol catalytic hydrogenation to cyclohexanol needs to be increased to complete the feed recycle. New arrangementThe reaction conditions of the photocatalysis process are mild, and the oxidation product KA oil can be directly used as a raw material for synthesizing adipic acid without a conversion process of catalytic hydrogenation. In addition, N is a photocatalytic compound invented by us₂Comparison of vanadium-substituted dodecaphosphomolybdic acid-hydrochloric acid photocatalytic system for preparing KA oil by oxidizing cyclohexane with O [ appl. Catal, B. 2016.182: 392-]The new designed photocatalysis process has no side reaction of chlorination, and the conversion efficiency, especially the selectivity of cyclohexanone, is obviously improved.

Disclosure of Invention

The invention aims to provide a synthesis method for preparing ruthenium hybridized deca-poly quaternary ammonium tungstate, which is used for obtaining different ruthenium compound hybridized deca-poly quaternary ammonium tungstate catalysts and is used for synthesizing N₂O is used as oxidant, acetonitrile is used as reaction medium, and under normal temperature and pressure, the visible light is used for catalytic oxidation of organic matter to synthesize oxygen-containing product.

The method for preparing the ruthenium hybrid deca-poly quaternary ammonium tungstate comprises the following steps:

step (1): 6.4g of sodium tungstate dihydrate and a ruthenium compound having a certain molar ratio were dissolved in 40 mL of water, and the resulting solution was placed in a three-necked flask and dissolved by boiling. Quickly transferring the three-neck flask filled with the reaction liquid into a water bath at 100 ℃, adjusting the pH to 2.0 by using a prepared hydrochloric acid solution, and carrying out magnetic stirring acidification polymerization reaction for 10min at the temperature;

step (2): slowly dripping the prepared tetraalkylammonium salt water solution into the polymerization solution with the temperature of 100 ℃ prepared in the step (1), continuously stirring to separate out a large amount of precipitate, adjusting the pH value to be 2.0 by using a hydrochloric acid solution in the process, and continuously carrying out magnetic stirring reaction for 25-35 min;

step (3) transferring the solid solution obtained in step (2) to a polytetrafluoroethylene reaction kettle, carrying out hydrothermal treatment at 80-120 ℃ for 6 ~ 24 hours, cooling, fully washing the filtered solid with water and ethanol, and 60^oAnd C, drying in vacuum for 12h to obtain the target catalyst ruthenium hybrid deca-poly-ammonium tungstate.

The invention has the following advantages:

(1) the required catalyst raw materials are easy to obtain, and the synthesis process is simple;

(2) the prepared ruthenium hybridized deca-poly ammonium tungstate can be used as N under normal temperature and pressure₂Efficient visible light catalyst for synthesizing oxygen-containing compound by O participating in oxidation of organic compound and N based on the photocatalytic oxidation process₂The environmental management and high value-added utilization of O, and the development of the synthesis of KA oil by cyclohexane oxidation under mild conditions and the realization of the raw material circulation for synthesizing adipic acid by KA oil oxidation have important economic and environmental significance.

Detailed Description

The following examples are further illustrative of the present invention and are not to be construed as limiting the invention to the particular examples set forth.