10 results about "Dimethyl oxalate" patented technology

The present application relates to a kind of preparation methods and systems of electronic grade dimethyl carbonate prepared from dimethyl oxalate, the method comprises the following steps: dimethyl oxalate is preheated and sent into decarboxylation reactor to carry out decarboxylation reaction, carbon monoxide, dimethyl carbonate and other light components are extracted from the top of decarboxylation reactor, and heavy components are extracted from the bottom of decarboxylation reactor;Carbon monoxide, dimethyl carbonate and other light components extracted are separated after gas-liquid, and liquid phase dimethyl carbonate is sent into rectifying column to carry out rectification purification;Electronic grade dimethyl carbonate product is obtained by crystallization purification in refrigeration crystallization device after rectification, and crystallization mother liquor returns rectifying column;Decarboxylation reactor is three-stage reaction tower, and rectifying section, reaction section, stripping section are sequentially from top to bottom.The present application is completely reacted by the design of three-stage decarboxylation reactor;Heavy components generated are extracted in real time, and catalyst stability is high;Electronic grade DMC is prepared by using rectifying column coupled with crystallization tower, and the yield of DMC is significantly improved.

This invention relates to the field of catalyst preparation technology, specifically to a copper-based catalyst for the hydrogenation of dimethyl oxalate and its preparation method. The catalyst is a Cu / SiO2 catalyst with a copper content of 5-25 wt% as the active component. It is prepared from raw materials such as a silicon source, a copper source, a hydroxyl protectant, and a hydrothermal promoter via a low-pressure ammonia stripping method. During the preparation process, by protecting the silanol hydroxyl groups and optimizing the ammonia stripping and complexation conditions, copper is highly dispersed and stable on the silicon support surface, effectively avoiding copper particle sintering and desilication problems. This catalyst exhibits excellent performance in the hydrogenation of dimethyl oxalate to ethylene glycol. Under reaction conditions of 170℃ and 2.8 MPa, the dimethyl oxalate conversion rate is ≥99%, the ethylene glycol selectivity is ≥97%, and the continuous operating time is ≥3000 h. It can significantly inhibit the formation of byproducts and carbon deposition, extend service life, and simultaneously reduce separation and purification energy consumption and catalyst replacement frequency. The raw materials used are conventional and controllable, and the preparation process is suitable for industrial production, showing broad application prospects.

The application discloses a method for preparing glycol and / or methyl glycolate by dimethyl oxalate hydrogenation, which comprises the following steps: (1) mixing methanol with hydrogen and then feeding into a heat exchanger for preheating to obtain a mixed material; (2) mixing the mixed material obtained in step (1) with dimethyl oxalate, heating through a feeding heater and then performing hydrogenation reaction to generate a reaction product comprising methyl glycolate and / or glycol. The method can greatly improve the heat exchange efficiency of the heat exchanger, reduce the heat load of the subsequent feeding heater, reduce steam consumption, thereby saving energy consumption, and avoiding the crystallization problem of dimethyl oxalate after being mixed with low-temperature hydrogen.

The application discloses application of a Mo / SiO2-Cu / ZnO / Al2O3 catalyst in preparation of ethanol through DMO hydrogenation catalysis, and Mo / SiO2 in the Mo / SiO2-Cu / ZnO / Al2O3 catalyst first catalyzes hydrogenation conversion of dimethyl oxalate into methyl acetate, and then Cu / ZnO / Al2O3 catalyzes hydrogenation conversion of the methyl acetate into ethanol. The Mo / SiO2-Cu / ZnO / Al2O3 catalyst is a two-stage filling catalytic system, and the filling modes include Mo-CuZnAl two-stage filling, Mo-mix-CuZnAl physical mixing filling and CuZnAl-Mo two-stage filling. The Mo / SiO2 catalyst and the Cu / ZnO / Al2O3 catalyst are simultaneously applied in preparation of ethanol through dimethyl oxalate hydrogenation synergistic catalysis, and the Mo / SiO2 catalyst and the Cu / ZnO / Al2O3 catalyst can exhibit stronger hydrogenation activity, excellent catalytic activity and higher ethanol selectivity.

A Mo / SiO2 catalyst and its preparation method are disclosed, along with its application in the hydrogenation catalytic synthesis of methyl acetate (MA) from dimethyl oxalate (DMO). The method employs a hydrogen thermal reduction process to prepare the Mo / SiO2 catalyst. Instead of calcining the ammonium molybdate precursor in a muffle furnace, it is directly decomposed at 500°C under H2 conditions to obtain a reduced Mo / SiO2 catalyst with strong hydrogenation activity. The strong interaction between the virus-like SiO2 and Mo enhances the antioxidant properties of the reduced Mo, allowing the Mo / SiO2 to be stored in air without being easily affected by instantaneous oxidation upon contact with air, thus maintaining its hydrogenation activity. When the Mo / SiO2 catalyst is applied to the hydrogenation synthesis of MA from DMO, under reaction conditions of 220°C, DMO can be completely converted and highly selectively converted to MA, providing a good reaction basis for the subsequent directional conversion of MA to EtOH.

The application provides a neutralization treatment system for acid intermediate products in an ethylene glycol preparation process, and belongs to the technical field of syngas-to-ethylene glycol, which comprises, in sequence, an alkali liquor preparation tank, an alkali liquor buffer tank and a static mixer which are communicated through pipelines; the alkali liquor preparation tank and the static mixer are respectively communicated with an ethylene glycol rectification tower through material adding pipes, and the ethylene glycol rectification tower is communicated with a dimethyl oxalate catalytic hydrogenation reactor; the alkali liquor preparation tank is communicated with an alkali liquor supply device through an alkali liquor adding pipeline; and a PH online monitor is arranged at the outlet of the static mixer. The neutralization treatment system for acid intermediate products in the ethylene glycol preparation process is simple in structure, convenient to operate, low in treatment cost and easy to be applied in industrialization.

This invention belongs to the field of catalytic chemical technology, disclosing a modified copper-based catalyst, its preparation method, and its application in selective hydrogenation. The modified copper-based catalyst is either an AgCu / SiO2 catalyst or a Cu / AgCuMgAl-LDO catalyst. The AgCu / SiO2 catalyst is prepared by a deposition precipitation method, while the Cu / AgCuMgAl-LDO catalyst is prepared by a co-precipitation method. Silver-modified copper-based catalysts can significantly improve the hydrogenation activity, target intermediate selectivity, and fixed-bed continuous operation stability of copper-based catalysts. The AgCu / SiO2 catalyst can effectively improve the yield of dimethyl oxalate hydrogenation to methyl glycolate, while the Cu / AgCuMgAl-LDO catalyst can significantly improve quinoline conversion and enhance long-term operational stability while maintaining high 1,2,3,4-tetrahydroquinoline selectivity.

The application discloses a system and method for directly producing battery-grade ferrous oxalate from dimethyl oxalate, which comprises a hydrolysis reactor, an adsorption stripping tower provided with adsorption fillers, which is used for stripping and removing impurities through countercurrent contact of oxalic acid solution and steam in the tower, and adsorption and removal of impurities, a precipitation reactor, which is used for mixing the oxalic acid solution and iron salt to perform a precipitation reaction and aging, so as to obtain a reaction product, and a product recovery unit, which is used for separating and recovering the reaction product to obtain the battery-grade ferrous oxalate, and recycling a synthesis mother liquor to an iron salt preparation unit. The application selectively removes DMO, MMO and methanol from the hydrolysis solution through steam stripping and removal of impurities, and the effect of removal of impurities is significantly better than that of conventional distillation. The adsorption removal of impurities is simultaneously performed in the stripping and removal of impurities, metal impurities are removed, the product has good crystallinity, regular crystal form and concentrated particle size distribution, and stable chemical purity, so that the requirements of battery-grade material precursors can be met, no additional energy consumption is increased, and the application has strong popularization.

The application discloses a supported catalyst and a preparation method and application thereof. The supported catalyst is composed of a carrier and Cu and phosphorus oxide supported on the surface of the carrier; the carrier is at least one selected from SiO2, Al2O3, ZnO, CeO2, ZrO2, MgO, Fe3O4, activated carbon and a molecular sieve; wherein the mass content of Cu is 5-30 wt%, the mass content of the phosphorus oxide is 0.01-10 wt%, and the rest is the carrier. The supported catalyst is used for catalyzing the hydrogenation of dimethyl oxalate to prepare methyl glycolate in a high-temperature range (250-300 DEG C). After the introduction of the auxiliary agent, the selectivity of the copper catalyst to the methyl glycolate product in the high-temperature range can be significantly improved, the high-temperature range is beneficial to improving the conversion rate of the dimethyl oxalate and the stability of the catalyst, and thus a higher yield of the target product can be obtained.

This invention discloses a catalyst for controlling the selective hydrogenation of dimethyl oxalate to prepare ethylene glycol or ethanol. The catalyst is a bifunctional nano-heterogeneous catalyst comprising a first active component, a second active component, and a support. The first active component is Cu, the second active component is Nb, and the highly active reaction site is Cu. 0 -Cu + The interface is composed of -Nb₂O₅, and the support is one or more of silicon dioxide, alumina, and zirconium oxide. This invention also discloses its preparation method and applications. In the catalytic hydrogenation reaction of dimethyl oxalate, the bifunctional nano-heterogeneous catalyst of this invention can be easily controlled by adjusting reaction conditions such as reaction temperature, reaction pressure, and the molar ratio of hydrogen to dimethyl oxalate to regulate the product and synthesize ethylene glycol or ethanol with high selectivity. Furthermore, the catalyst exhibits extremely high stability and catalytic activity, and high utilization rate of the active component.