13 results about "Polyoxymethylene dimethyl ethers" patented technology

The invention discloses an internal-acid and external-alkali type organic-inorganic hybrid molecular sieve catalyst as well as a preparation method and application thereof, and belongs to the technical field of heterogeneous catalytic materials and chemical processes. According to the catalyst, a hydrogen type Beta molecular sieve is used as an acidic inner core, polyvinylpyrrolidone (PVP) is used as an organic shell, and a unique inner-acid outer-alkali structure is formed. The preparation method comprises the following steps: hydrothermally synthesizing a hydrogen type Beta molecular sieve with a specific silica-alumina ratio, and then coating PVP through surface adsorption. The catalyst is used for catalyzing the condensation of methylal and trioxymethylene under mild conditions (40-70 DEG C and normal pressure) to prepare polyoxymethylene dimethyl ethers (DMMn). The PVP shell covers acidic sites on the outer surface of the molecular sieve to form an external neutral / weak base and internal strong acid microenvironment, so that the secondary side reaction of the product is effectively inhibited, the trioxymethylene conversion rate of more than 98% and the DMMn selectivity of more than 96% can be obtained in the reaction at 50 DEG C and normal pressure, the product distribution can be regulated and controlled, and the traditional Anderson-Schulz-Flory distribution limitation is broken through. The catalyst disclosed by the invention has the advantages of high activity, high selectivity, mild conditions and easiness in separation, and has a good industrial application prospect.

The application discloses a catalyst for preparing polyoxymethylene dimethyl ethers by directly oxidizing methanol, a preparation method and application thereof, and belongs to the field of catalyst preparation and application. The metal oxide and the acidic molecular sieve are effectively coupled to prepare a bifunctional composite catalyst with a core-shell structure, the composition and proportion of the metal oxide and the acidic molecular sieve are regulated, and high-selectivity synthesis of polyoxymethylene dimethyl ethers by directly oxidizing methanol is realized. The unique core-shell structure can effectively regulate the distance and distribution between the two types of active sites, significantly promote the gradual chain growth of methanol oxidation, and obviously inhibit the occurrence of side reactions such as methanol dehydration to dimethyl ether and deep methanol oxidation, so that the high-selectivity synthesis of polyoxymethylene dimethyl ethers by directly oxidizing methanol is realized. The catalyst preparation process is simple and easy to operate, and the one-step oxidation of methanol to prepare polyoxymethylene dimethyl ethers has the advantages of short flow, good atom economy and green process.

This invention discloses a rare-earth element-containing cationic catalyst, its preparation method, and its application, belonging to the field of catalyst technology. Using 732 polystyrene sulfonic acid resin as a support, the target catalyst is prepared in four steps: pretreatment, zirconium coordination modification, aminobisphosphonic acid ligand grafting, and rare-earth ion chelation loading. This invention constructs a Brønsted-Lewis dual-acid synergistic catalytic system through directional structural design, achieving both ultra-stable rare-earth loading and retention of strong acidic sites, significantly improving the catalyst's water resistance, catalytic activity, and cycle stability. This catalyst can efficiently catalyze the synthesis of polyoxymethylene dimethyl ether from industrial formaldehyde aqueous solution and methyl acetal, exhibiting excellent formaldehyde conversion and target product selectivity. It is suitable for both batch and continuous production processes and has good prospects for industrial application.

This invention discloses a core-shell catalyst for the dehydrogenation of methanol to polyoxymethylene dimethyl ether (POMDE), its preparation, and its application. The catalyst comprises an acidic molecular sieve, a metal active component, and aluminum-containing mesoporous silica. The acidic molecular sieve serves as the core structure, with the metal active component coating the surface of the acidic molecular sieve to form a first coating layer, and the aluminum-containing mesoporous silica coating the surface of the metal active component to form a second coating layer. The prepared core-shell catalyst uses the middle acidic molecular sieve and the outermost aluminum-containing mesoporous silica as acidic sites, and the middle metal active component as a dehydrogenation site. By integrating these two reaction sites, a bifunctional catalyst is constructed, achieving in-situ coupling of the two-step reactions of methanol dehydrogenation to formaldehyde and methanol-formaldehyde condensation to POMDE. This not only simplifies the reaction steps but also improves the selectivity of the reaction.

The invention relates to a process for the preparation of H3C-O-(CH2O) 2-CH3 (OME2), comprising the following steps: introducing a reactant composition comprising methylal and one or more polyoxymethylene dimethyl ethers having the formula H3C-O-(CH2O) n-CH3, 3 < = n < = 20 (OME3-20) into a reactor and converting it into a product mixture comprising OME2, methylal and one or more polyoxymethylene dimethyl ethers OME3-20, introducing the product mixture into a distillation unit D1 and separating the product mixture into a first fraction, which contains methylal and leaves the distillation unit D1 as an overhead stream KSD1, and a second fraction, which contains OME2 and one or more polyoxymethylene dimethyl ethers OME3-20 and leaves the distillation unit D1 as a bottom stream SSD1, -introducing the bottom stream SSD1 into the distillation unit D2 and separating the bottom stream SSD1 into a first fraction comprising OME2 and leaving the distillation unit D2 as an overhead stream KSD2 and into a second fraction comprising one or more polyoxymethylene dimethyl ethers OME3-20 and leaving the distillation unit D2 as a bottom stream SSD2.

The invention discloses a method for preparing polyoxymethylene dimethyl ether in an anhydrous formaldehyde system, and belongs to the field of new energy synthetic fuel and environment-friendly solvent preparation. Aiming at the problems that a water-containing system in the prior art is low in reaction efficiency, separation of residual formaldehyde and formic acid is interfered, and environmental protection and economy are insufficient, the method comprises the following steps: P1, reacting anhydrous gas formaldehyde and methylal with the purity of more than or equal to 99.0% serving as raw materials in a radial flow fixed bed reactor under the catalysis of macroporous cation exchange resin at the temperature of 50-80 DEG C, the pressure of 0.2-0.6 MPa and the air speed of 0.4-1.0 h <-1 > to generate a product containing DMM2-6; under the hydrogenation catalysis of P2 non-supported NiMoW, hydrogenation is carried out at the temperature of 40-80 DEG C and the pressure of 1.0-4.0 MPa to remove aldehyde acid; the P3 is subjected to normal-pressure-reduced-pressure rectification to obtain DMM2 with the purity being larger than or equal to 98.0% and DMM3-6 with the purity being larger than or equal to 98.5%, and side line materials of the first rectification tower are recycled and reused. The formaldehyde conversion rate is greater than or equal to 92%, the DMM2-6 selectivity is greater than or equal to 98%, the product is free of sulfur-nitrogen aromatic hydrocarbons and waste lye, the energy consumption is low, and the raw material utilization rate is high.

The utility model discloses a polyoxymethylene dimethyl ether rectification system which comprises a first rectification tower assembly and a second rectification tower assembly, an outlet of the first rectifying tower assembly is respectively connected with an inlet of the reaction device and an inlet of the second rectifying tower assembly, DMM3-6 in DMMn reaction products is separated from other products, the separated DMM2, DMM7-13 and paraformaldehyde are sent back to the inlet of the reaction device, and DMM1 and methanol are sent into the second rectifying tower assembly; an outlet of the second rectifying tower assembly is connected with an inlet of the reaction device, and DMM1 after methanol is separated is sent back to the reaction device. According to the polyoxymethylene dimethyl ether rectification system disclosed by the utility model, separation and cyclic utilization of byproducts generated after DMMn synthesis reaction, particularly separation of methanol, are realized, refined DMM3-6 is obtained, not only is the product purity improved, but also the components of the byproducts are fully utilized, and the consumption of raw materials is effectively reduced.

The invention discloses a polyoxymethylene dimethyl ether synthesis process based on a high-load acidic catalyst, and belongs to the technical field of chemical production processes. The process comprises the following steps: by taking methanol or dimethyl ether as a raw material, carrying out molecular sieve dehydration pretreatment, carrying out one-step oxidative condensation in a fixed bed reactor by adopting a high-load acid catalyst, standing for liquid separation, carrying out double-tower rectification, carrying out molecular sieve dehydration and filtering by a filter membrane to finish product refining. Wherein a high-load acidic catalyst mesoporous silica is used as a carrier, a Mo-V / W composite oxidation active center is constructed, gradient acidic sites of strong acid in a pore channel-strong acid in a pore channel inlet / surface are matched, and the outer surface is subjected to hydrophobic passivation treatment, so that multifunctional synergistic catalysis is realized. According to the process, the traditional complex process is simplified, the selectivity and the product purity of the target product are greatly improved, the catalyst structure is stable, the service life is long, the obtained product meets the diesel oil mixing requirement, effective combustion supporting and emission reduction can be achieved under high altitude and other scenes, and the good industrial application prospect is achieved.

The invention relates to the technical field of chemical engineering, in particular to a polyoxymethylene dimethyl ether synthesis device and a synthesis method.The polyoxymethylene dimethyl ether synthesis device comprises a stirring and dissolving kettle, and the lower end of the stirring and dissolving kettle is fixedly connected with a conveying valve used for controlling the feeding effect of polyoxymethylene dimethyl ether; the raw material mixing effect can be enhanced through the porous ceramic membrane and the nanoscale dispersion membrane in the stirring and dissolving kettle in the device, and raw materials are refined and dispersed more sufficiently; a catalytic enhanced membrane and a supported catalytic membrane in the composite catalytic reactor can enable materials to be in full contact with a catalyst, so that the catalytic reaction efficiency is improved; the efficient rectification filler of the methylal refining tower, the stepped separation filler of the rectification separation tower, the selective permeable membrane and the hollow fiber separation membrane of the membrane separation auxiliary device and the like can purify and separate materials for multiple times, so that the synthesis efficiency and the product purity of polyoxymethylene dimethyl ether are remarkably improved.

This invention discloses a fuel for replacing gasoline in engines and its preparation method, belonging to the field of new energy fuel technology. The fuel comprises methanol, naphtha, a composite cosolvent, a composite corrosion inhibitor, a composite power enhancer, a cold start aid, a lubricant, and an antioxidant. The composite cosolvent is composed of tert-butanol, dimethyl carbonate, and alkyl glycosides, achieving wide-temperature-range homogeneous stability and strong water resistance. The composite corrosion inhibitor is composed of benzotriazole, organic amine esters, and fatty amines, effectively inhibiting metal corrosion. The composite power enhancer is composed of isooctyl nitrate and polyoxymethylene dimethyl ether, improving octane number and combustion efficiency. Combined with the cold start aid, lubricant, and antioxidant, the resulting fuel exhibits excellent low-temperature stability, good water resistance, low corrosivity, good cold start performance, power output close to that of traditional gasoline, reduced exhaust emissions, good storage stability, and low raw material costs, effectively replacing traditional gasoline.

The invention relates to the technical field of diesel engine tail gas purification, in particular to a tail gas particle purifying agent which is composed of the following components in percentage by mass: 30-40% of polyoxymethylene dimethyl ether, 5-10% of cerium naphthenate, 10-15% of acrylic acid, 1-7% of polyether amine, 3-8% of isooctyl nitrate, 3-5% of acetone and 15-20% of isopropanol. The working temperature range of passive regeneration is widened, the advantages are obvious especially under the low-temperature or low-load working condition, and the DPF blocking risk can be reduced.

The invention discloses a method and a system for preparing polyoxymethylene dialkyl ether with a low polymerization degree, and belongs to the technical field of oxygen-containing fuels and environment-friendly solvents, the method comprises the following three core processes: P1 raw material reaction: taking anhydrous polyoxymethylene dimethyl ether (DMM2) as a methoxy donor, and reacting with alkyl alcohol in a fixed bed reactor to obtain a reaction product; carrying out a catalytic reaction through strongly acidic macroporous cation exchange resin at the reaction temperature of 60-90 DEG C and the pressure of 0.6-0.8 MPa; a NiCu / gamma-Al2O3 catalyst is adopted in P2 hydrofining, trace formaldehyde is reduced into methanol, and the formaldehyde atom recovery rate is larger than or equal to 99%; and P3 three-tower rectification is carried out to recover light components in sequence, unreacted DMM2 and alkyl alcohol are circulated, and finally, methyl-alkyl mixed terminated SPODEn and same alkyl terminated TPODEn with the polymerization degree n being equal to 1 or 2 are obtained through separation, wherein the methyl-alkyl mixed terminated SPODEn and the same alkyl terminated TPODEn have the polymerization degree n being equal to 1 or 2. A whole-course anhydrous system is constructed, water-alcohol azeotropy is avoided, and the comprehensive utilization rate of raw materials is larger than or equal to 95%; the product purity is greater than or equal to 98%, the energy consumption is reduced by more than 30% compared with the traditional process, and the method has excellent performances of high cetane number, low condensation point and the like, can be widely applied to the fields of diesel oil blending, environment-friendly solvents and the like, and is suitable for industrial large-scale production.

The application discloses a kind of negative carbon type compression ignition clean fuel and its preparation method and use, belong to clean alternative fuel technical field.The fuel is by 45-55% hydrogenated vegetable oil, 20-30% green fischer-tropsch synthesis alkane, 10-20% polyoxymethylene dimethyl ether, 0.5-8% biological ester and 0.5-5% composite additive composition, does not contain any fossil hydrocarbon component, and whole life cycle carbon intensity≤-20g CO2eq / MJ.The application prepares fuel by raw material pretreatment, multiphase shearing mixing, additive compounding, on-line quality adjustment, product cetane number≥70, flash point>70℃, can be directly used in various compression ignition internal combustion engine, only needs light seal piece adaptation, with the advantages of negative carbon environmental protection, safe and economical, ready-to-use compatible, can effectively help traffic field deep decarbonization.