40results about How to "Selectivity unchanged" patented technology

A catalyst for preparing ethanediol by hydrating epoxy ethane is composed of the oxide of carried Nb, at least one element or compound chosen from V, Mo, W, Sn and Pb, and at least one element or compound chosen from La, Pr and Nd. Its advantages are low consumption of water and energy and no corrosion and pollution.

The invention relates to a method for preparing ethylene glycol by catalytic hydration of ethylene oxide, which mainly solves the problem that the non-catalytic hydration water ratio of ethylene oxide in the past is too high, or the liquid acid catalyst used for catalytic hydration corrodes equipment, pollutes the environment, and solidifies Acid catalysts are poor in stability or their stability and activity cannot reach the ideal state at the same time. Provide a method for the catalytic hydration of ethylene oxide to prepare ethylene glycol. The solid acid catalyst used in this method uses niobium compounds as the main active component , using at least one selected from germanium, tin, lead, antimony, phosphorus, sulfur, iron or cobalt as additives, reacting to prepare ethylene glycol under conditions of lower water ratio, which can greatly reduce the need for processing excess water The catalyst used not only has good activity and selectivity, but also has excellent stability, prolongs the operation period of the catalyst, and has the characteristics of low energy consumption and low production cost. It can be used in the industrial production of ethylene glycol.

The invention provides a preparation method of an ethanol Pt-Sn / Li-Al-O catalyst through acetic acid hydrogenation and belongs to the technical field of catalyst preparation. The method comprises the steps of (1) immersing Al2O3 into a soluble metal salt solution containing lithium, drying and roasting to obtain a Li-Al-O carrier; and (2) immersing the obtained Li-Al-O carrier into a soluble metal salt solution containing active components Sn and Pt and then drying and roasting to obtain a Pt-Sn / Li-AlO catalyst. The Li-Al-O of a lithium aluminum spinel structure is adopted as the carrier, the surface property of the carrier is stable and the dispersibility of the active components can be improved, thereby improving the activity and the stability of a finished product catalyst. The prepared catalyst has relatively low surface acid property and the selectivity of ethanol can be effectively improved. The method is applied to preparation of the ethanol through acetic acid hydrogenation, so that the acetic acid conversion rate can reach 100% and the ethanol selectivity can reach over 95%. The catalyst prepared through the preparation method has good stability, and the catalyst activity and the ethanol selectivity are basically kept invariable after reaction for 500h.

The invention relates to a method for preparing alkylene dihydric alcohols, and mainly solves the problems of short service life and poor heat resistance of catalysts used in the prior art under conditions of high conversion rate and selectivity. The present invention uses alkylene oxide and water as raw materials, at a reaction temperature of 60 to 150°C, a reaction pressure of 0.5 to 2.0 MPa, a water / alkylene oxide molar ratio of 5 to 15:1, and a liquid space velocity of 3 to 10 MPa. 6 hours -1 Under the conditions, the raw material is contacted with the composite resin catalyst to generate alkylene glycol, wherein the composite resin catalyst includes monomers, comonomers, nanomaterials, initiators and auxiliary components, and the composite resin uses OH - , Cl - 、HSO 4 - 、HCO 3 - or HCOO - The technical scheme of anion compound treatment solves this problem well, and can be used in the industrial production of ethylene oxide catalytic hydration to form dihydric alcohol.

The invention relates to a two-section type switchable tubular reactor and a method for preparing alcohol through aldehyde gas phase hydrogenation by using the same. The reactor comprises an I section reactor, an II section reactor, a valve and pipelines both capable of switching the feeding sequence of raw materials of the two section reactors, and a valve and pipelines both capable of controlling a reaction temperature of the two section reactors. By adopting the two-section switchable tubular reactor for the aldehyde gas phase hydrogenation, the activity of a catalyst in the reactor having the precedent feeding sequence is reduced, but the activity of the catalyst in the reactor having the later feeding sequence is reduced a little after the reaction lasts for a period of time. Through the valve control, the method for preparing alcohol through aldehyde gas phase hydrogenation by using the two-section type switchable tubular reactor has the advantages of realizing the switching of the feeding sequence of the two section reactors and the control of the reaction temperature, increasing the utilization rate of the catalyst, prolonging the service life of the catalyst, prolonging the operating time of a device, saving production cost and the like.