508 results about "Polyoxymethylene dimethyl ethers" patented technology

The invention relates to a method for preparing polyoxymethylene dimethyl ether. The invention mainly solves the problems of the prior art that: catalyst is corrosive, and is complexly separated from reactant, and energy consumption is high. The method adopts methanol and trioxymethylene as materials, the materials react with catalyst by way of contact under mild conditions, so that the polyoxymethylene dimethyl ether is produced, wherein the catalyst is selected from Beta zeolite, ZSM-5 molecular sieve, MCM-22 and MCM-56 zeolite molecular sieve. The method effectively solves the problems, and can be used in the industrial production of polyoxymethylene dimethyl ether.

The invention relates to a catalyst for synthesis of polyoxymethylene dimethyl ether, application of the catalyst in synthesis of polyoxymethylene dimethyl ether and a method for synthesizing polyoxymethylene dimethyl ether, and mainly aims to solve the problem that the catalyst has low selectivity and low yield for polyoxymethylene dimethyl ether which has a polymierization degree n of 2-10 in the prior art. The technical problem can be well solved by adopting a technical scheme that the catalyst is a metal ion modified hydrogenous strong-acid ion exchange resin, wherein the modifying metal is at least one of Al, Fe, Sn and Zn; and the ion exchange degree of the modifying metal in the catalyst is more than zero and less than or equal to 50 percent. The catalyst can be used in industrial production of polyoxymethylene dimethyl ether.

The invention provides a method for continuous production of polyformaldehyde dimethyl ether. The method is characterized by comprising the following steps: a) feeding dimethoxymethane and hot-melted paraformaldehyde into a fixed bed reactor and adopting an acidic resin catalyst, so as to prepare polyformaldehyde dimethyl ether (DMM3-8), wherein the reaction temperature is 120-180 DEG C and the pressure is 0.1-10 MPa; b) cooling the reaction product, and then performing adsorptive separation through a dehydrating tower, so as to obtain polyformaldehyde dimethyl ether of which most water, cytidine glycol and hemiacetal are desorbed; c) feeding the polyformaldehyde dimethyl ether subjected to desorption into a distillation tower for separation, wherein most of a low-boiling component (dimethoxymethane (DMM)), poly-di-formaldehyde dimethyl ether (DMM2), a by-product (methanol) and triformol are extracted first, and then the materials in a tower kettle are fed into a rectifying tower in the next step, so as to extract the rest of the DMM2 and the triformol; and d) returning the low-boiling component (dimethoxymethane (DMM)), the methanol, the DMM2 and the triformol, which are evaporated out by the distillation tower and the rectifying tower in the last step, into the fixed bed reactor to continue to react to prepare polyformaldehyde dimethyl ether.

The invention relates to a catalytic synthesis method for polyoxymethylene dimethyl ethers (PODE) by molecular sieves, mainly solving the problem of relatively high cost in the conventional method which adopts trioxymethylene as a raw material. In the method, methanol, methylal and paraformaldehyde are adopted as raw materials based on the mass ratio of (0-10): (0-10):1, the raw materials contactwith a catalyst to react and generate PODE, wherein the dosages of the methanol and the methylal can not be zero at the same time; the reaction temperature is 70-200 DEG C; the reaction pressure is 0.1-6MPa; and the adopted catalyst is selected from at least one of beta zeolite, X zeolite, Y zeolite, ZSM-5 molecular sieve, MCM-22, MCM-56, UZM-8 or SAPO-34 molecular sieve. The technical scheme adopted by the invention solves the above problem preferably, thus being applicable to industrialized production of the PODE.

The invention relates to a synthetic method for polyoxymethylene dimethyl ether, and mainly overcomes the problem of relatively high cost in a conventional method for synthesizing polyoxymethylene dimethyl ether by using trioxymethylene as a raw material. The synthetic method takes use of methanol, methylal and paraformaldehyde as raw materials, wherein a mass ratio of methanol to methylal to paraformaldehyde is 0-10 : 0-10 : 1; and the usage amount of methanol and methylal is not zero at the same time; and the raw materials are contacted with a catalyst under a reaction pressure of 0.2-6 MPa to produce polyoxymethylene dimethyl ether (CH3O(CH2O)nCH3), wherein the used catalyst is selected from activated carbon. By adopting the above technical solution, the problem is overcome relatively well; and the synthetic method can be used for industrial production of polyoxymethylene dimethyl ether.

The invention relates to a method for synthesizing PODE (polyformaldehyde dimethyl ether), which mainly solves the problems of high content of methylal and low yield coefficient of poly products in the traditional process of synthesizing the PODE with carbinol and trioxymethylene as raw materials. The method adopts the carbinol, the methylal and the trioxymethylene as the raw materials, and the raw materials contact a catalyst under conditions that reaction temperature is 50-200 DEG and reaction pressure is 0.1-10 MPa so as to react to generate the PODE, wherein the catalyst is at least one of Beta zeolum, ZSM-5 molecular sieve and MCM-22 or MCM-56 zeolum molecular sieve. The method preferably solves the problems and can be used for the industrial production of the PODE.

The invention discloses a multi-section reaction tower for polyoxymethylene dimethyl ether synthesis and a polyoxymethylene dimethyl ether synthesis process unit. A tower body of the multi-section reaction tower comprises at least two layers of reaction sections from top to bottom; each layer of reaction section is provided with a tower plate and forms a bent passageway; catalysts are arranged between the tower plates in a filling manner; gas ascension pipes are arranged between the adjacent layers of reaction sections; a gas phase outlet is formed in the tower top of the reaction tower; and each layer of reaction section is provided with an inlet with a valve and an outlet with a valve. According to the multi-section reaction tower for polyoxymethylene dimethyl ether synthesis and the polyoxymethylene dimethyl ether synthesis process unit, the conversion equilibrium point of the reaction is effectively controlled, the advancement of the reaction equilibrium toward bigger polymers is effectively deferred, the conversion rate and the selectivity are improved, the reaction is carried out under the conditions that the catalyst activity is relatively high and the temperature does not excessively influence the reaction equilibrium, and good conversion rate and selectivity are obtained.

The invention relates to a method for preparing polyoxymethylene dimethyl ether, which mainly solves the problems of low conversion rate of trioxymethylene and low selectivity of DMM 3-8 in current polyoxymethylene dimethyl ether production. According to the invention, under the effective reaction condition, methylal and trioxymethylene are reacted in a catalytic distillation tower, a components separation is performed simultaneously, steam at the top of the tower is condensed and then reflowed, a first part of the materials at the bottom of the tower is vaporized by a reboiler and returned back to the catalytic distillation tower, a second part of the materials is taken as produced liquid, the mass ratio of the first part to the second part is 1-10:1, wherein the trioxymethylene enters from the top of the tower, methylal can enter from any position from a stripping section to the tower top. The technical scheme of catalyst capable of being a heterogeneous phase acidic catalyst can effectively solve the problem, and the catalyst can be used for industrial production of polyoxymethylene dimethyl ether.

The invention discloses a process method for preparing polyoxymethylene dimethyl ethers. The method includes the steps that formaldehyde gas is cooled to 100 DEG C and below, so that vapor is removed; dehydrated gas formaldehyde is directly absorbed by a mixture of polyoxymethylene dimethyl ethers DMM1-2 and polyoxymethylene dimethyl ethers DMM6-10 of different degrees of polymerization, then a reaction is conducted, polyoxymethylene dimethyl ethers DMM 3-5 are prepared, and DMM1-2 and DMM 6-10 with the DMM 3-5 separated continuously serve as raw materials and are recycled. According to the method, formaldehyde gas generated by methanol oxidation is cooled to 100 DEG C and below, vapor is condensed into liquid water, the purpose of dehydration is achieved, and due to the fact that water in the formaldehyde is removed before being absorbed by reactant, and the situations that a polycondensation reaction occurs and device is blocked by paraformaldehyde generated by formaldehyde polycondensation are avoided; the mixture of the DMM1-2 and DMM6-10 also participates in a polymerization reaction and a depropagation reaction in the cyclic process and is finally converted to the polyoxymethylene dimethyl ethers DMM3-5 of the target degree of polymerization. The method is simple in process and easy to operate, the speed for generating the DMM3-5 is high, the conversion rate of the DMM3-5 is high, and energy consumption and equipment investment are lowered.

The invention aims to solve the technical problem that long-term continuous production operation is difficult due to the fact that materials block the tops of rectifying towers in the PODE (polyoxymethylene dimethyl ether) purification process with a rectification method. The adopted technical scheme comprises steps as follows: (a) a reaction mixture obtained by a reaction synthesis unit firstly enters a first rectifying tower, a first fraction mainly containing methylal is removed through separation, and first tower bottoms are obtained; (b) the first tower bottoms enter an extraction unit and are subjected to extraction with a two-phase extraction agent containing an organic solvent and an aqueous phase, an extract phase containing PODEn (n=2-8) and an organic solvent is obtained, and a raffinate phase is an aqueous phase containing formaldehyde; (c) the extract phase sequentially enters a second rectifying tower, a third rectifying tower and a fourth rectifying tower for rectification, and a second fraction containing an organic solvent, a third fraction containing high-purity PODEn (n=2) and a fourth fraction containing PODEn (n=3-5) are obtained respectively.

The invention provides a process for preparing polyoxymethylene dimethyl ether represented by general formula (1). The process for preparing the polyoxymethylene dimethyl ether is characterized by subjecting methanol, methylal and /or dimethyl ether and formaldehyde and /or paraformaldehyde to reaction under the action of an acid catalyst and a water absorbing agent. The general formula (1) is as follows.

The invention relates to a method for preparing polyformaldehyde dimethyl ether by using a loaded niobium oxide catalyst. The method is characterized by comprising the following steps of: a) preparing the polyformaldehyde dimethyl ether by a catalytic reaction, wherein the molar ratio of methylal to trioxymethylene is 0.5 to 5, loaded niobium oxide is taken as a catalyst, the using amount of the catalyst is 0.1 to 5 percent of the molar weight of a reactant, the reaction temperature is between 100 and 200 DEG C, reaction time is between 10 minutes and 48 hours and reaction pressure is between 0.1 and 10 MPa; b) rectifying and separating, namely, separating a low-boiling point component, namely, methylal DMM, polydiformaldehyde dimethyl ether DMM2 and unreacted trioxymethylene out and separating polyformaldehyde diformaldehyde DMM3-8 out, wherein a small amount of polyformaldehyde dimethyl ether DMMn with a high polymerization degree exists at the bottom of a kettle and n is more than 8; and c) adding a small amount of fresh trioxymethylene into the methylal, the polydiformaldehyde dimethyl ether DMM2 and the unreacted trioxymethylene which are separated out in the previous step and continuing reacting so as to obtain the polyformaldehyde diformaldehyde DMM3-8 which is suitable to be taken as a diesel engine blending combustion component. Therefore, the utilization ratios of raw materials are increased.

It is related to a method for preparing polyoxymethylene dimethyl ethers by a continuous acetalation reaction of trioxymethylene and methanol or methylal catalyzed by an ionic liquid. The processing apparatus used in the method includes a reaction zone, a separation zone, a catalyst regeneration zone and a product dehydration zone. A manner of circulating tubular reaction is used, resulting in a high external heat exchange efficiency, a simple structure of design and a low investment. A film evaporator is used, realizing a rapid separation and recycling of the light component, with a high separation efficiency. The separation of the catalyst solution from the crude product is simple, thereby realizing the regeneration and recycling of the catalyst.

It is disclosed a method for preparing polyoxymethylene dimethyl ethers by continuous polymerization and acetalation reactions. The method may include two steps: performing a polymerization reaction of an aqueous formaldehyde solution under catalysis of an ionic liquid IL I to obtain a mixed aqueous solution of trioxymethylene and formaldehyde; and an acetalation reaction of the mixed aqueous solution of trioxymethylene and formaldehyde with methanol is performed under catalysis of an ionic liquid IL II to prepare polyoxymethylene dimethyl ethers. The method may use an aqueous formaldehyde solution as a starting material to prepare polyoxymethylene dimethyl ethers by continuous polymerization and acetalation reactions, achieving a high use ratio of formaldehyde. A film evaporator is used in the invention, realizing a rapid separation and recycling of the light components, with a high separation efficiency. The separation of the catalyst is simple, thereby realizing recycling of the catalyst.

The invention relates to a method for preparing novel clean synthetic diesel oil and mainly solves the problems that the conventional diesel oil is low in cetane number and is combusted insufficiently in an engine, and a large amount of solid pollutant, COx and NOx are discharged. The method mainly comprises the following steps of: uniformly mixing 5 to 30 mass percent of diesel oil substitute component, 5 to 30 mass percent of additive and 40 to 90 mass percent of diesel oil at normal temperature, standing for 8 to 10 hours, and after liquid is clarified, canning to obtain the novel clean synthetic diesel. The diesel oil substitute component is polyformaldehyde dimethyl ether, methylal or mixture of polyformaldehyde dimethyl ether and methylal in any ratio. By the method, the combustion efficiency of the synthetic diesel oil is improved, the discharge of free carbon and harmful gas is reduced, the quality of the synthetic diesel oil is improved, cost is reduced, a novel way from coal to oils is developed, and the method has good social and economic benefit. The novel clean synthetic diesel oil can be used independently and can also be mixed with petroleum diesel oil to be used, and the engine is not needed to be changed.

The invention provides a method for preparing polyoxymethylene dimethyl ether carboxylate and/or methyl methoxy acetate which serves as an intermediate for producing ethylene glycol. The method comprises the step of enabling a raw material, namely polyoxymethylene dimethyl ether or methylal, together with carbon monoxide and hydrogen gas to react in a desiliconisation modified acidic molecular sieve catalyst loaded reactor under appropriate reaction conditions without adding other solvents, so as to prepare corresponding products, wherein a reaction process is of gas-liquid-solid three-phase reaction. According to the method provided by the invention, the conversion ratio of the raw material polyoxymethylene dimethyl ether or methylal is high, the selectivity of each product is high, the service life of a catalyst is long, external solvents are not required to be used, reaction conditions are relatively mild, and continuous production can be carried out, so that the method has industrial application potential. Furthermore, the obtained products can be used for producing ethylene glycol through hydrolyzing after hydrogenating or hydrogenating after hydrolyzing.

The invention discloses a method for adsorption, membrane separation and dehydration of polyoxymethylene dimethyl ether. The method comprises the following steps: introducing a gas phase material flow raw gas from the top of an adsorption tower I, and performing adsorption reaction in the adsorption tower I; putting a molecular sieve in the adsorption tower I into a regeneration stage after adsorption, and introducing the gas phase material flow raw gas into an adsorption tower II to perform adsorption reaction; at the regeneration stage, under the action of a vacuum pump, discharging a desorption gas from the top of the adsorption tower I, performing membrane separation treatment on the desorption gas, introducing the desorption gas into a raw gas pipeline, and performing adsorption deep dehydration in the next step; after the regeneration in the adsorption tower I, entering an adsorption state again; and after the adsorption in the adsorption tower II, entering the regeneration stage. By adopting the process, on the basis of ensuring the high purity of a product, a high yield is obtained, the desorption gas does not need to be returned to the previous stage distillation process for retreatment at the same time, and the complete independent running of a dehydration working section is realized, so that the method has obvious technical and economic advantages.

The invention needs to solve a technical problem of being hard to operate continuously in long-term when materials block an overhead of rectifying column in the process of purifying the PODE by distillation. An adopted technical scheme includes following steps: (a) a reaction mixture, produced through a reactive synthesis unit, enters into a first rectifying column. A first fraction, mainly including Methylal, is separated and a first column residue is produced; (b) the first column residue and make-up water enter into a second rectifying column, and a second column residue and a second overhead of rectifying column light ends including PODE2 raw material are produced by separation; (c) after adding extraction agent in the second overhead of rectifying column light ends, raffinate is separated and extract phase is produced; (d) a second column residue enters into a fourth rectifying column. Production fraction containing PODE 3-5 is separated by the overhead of rectifying column.

The invention relates to a process method for preparing polyformaldehyde dimethyl ether from methanol. The process method adopts an oxidation reaction zone and a reaction rectification zone, wherein the oxidation reaction zone comprises a methanol storage tank (1), a preheater (3), a fixed bed reactor (5) and a pre-mixing tank (7); the oxidation reaction zone comprises the following process steps: preheating methanol to be gasified, mixing with preheated air, feeding into the fixed bed reactor, performing catalytic oxidation on a formaldehyde catalyst prepared through methanol oxidization, thereby generating formaldehyde, feeding the formaldehyde into the pre-mixing tank (7), pre-mixing the formaldehyde with methanol and a circulated and recycled mixture inside the pre-mixing tank before being reacted, and further feeding into the reaction rectification zone; the reaction rectification zone comprises a reaction rectification tower (12), three serially connected separation rectification towers and a product storage tank (28) in sequence; the three serially connected separation rectification towers are respectively a first separation rectification tower (17), a second separation rectification tower (22) and a third separation rectification tower (25). The process method has the characteristic that the yields of n=3 and n=4 are high.

The invention discloses a method for preparing polyformaldehyde dimethyl ether by adopting a supported niobium oxide catalyst, which is characterized by comprising the following steps of: a) performing catalytic reaction to prepare the polyformaldehyde dimethyl ether, wherein a molar ratio of the dimethoxymethane to trioxymethylene is 0.5 to 5; supported niobium oxide is taken as a catalyst and accounts for 0.1 to 5 percent based on the total mass of reactants; the reaction temperature is between 100 and 200 DEG C; the time is between 10 minutes and 48 hours; and the reaction pressure is between 0.1 and 10MPa; b) performing rectification separation, namely separating a low-boiling point component dimethoxymethane DMM, polydiformaldehyde dimethyl ether DMM2 and the unreacted trioxymethylene, and separating polyformaldehyde diformaldehyde DMM3-8, wherein a kettle bottom is provided with high-polymerization degree polyformaldehyde dimethyl ether DMMn, and n is more than 8; and c) adding a small amount of fresh trioxymethylene into the dimethoxymethane, the diformaldehyde dimethyl ether DMM2 and the unreacted trioxymethylene which are separated in the step b and continuously reacting to prepare the polyformaldehyde diformaldehyde DMM3-8, which is suitable to be used as a diesel fuel-blended component so as to improve the utilization rate of the raw materials.

The invention provides a method for preparing polyoxymethylene dimethyl ether carboxylate and/or methyl methoxy acetate which serves as an intermediate for producing ethylene glycol. The method comprises the step of enabling a raw material, namely polyoxymethylene dimethyl ether or methylal, together with carbon monoxide and hydrogen gas to react in an acidic molecular sieve catalyst loaded reactor under appropriate reaction conditions without adding other solvents, so as to prepare corresponding products, wherein a reaction process is of gas-liquid-solid three-phase reaction. According to the method provided by the invention, the conversion ratio of the raw material polyoxymethylene dimethyl ether or methylal is high, the selectivity of each product is high, the service life of a catalyst is long, external solvents are not required to be used, reaction conditions are relatively mild, and continuous production can be carried out, so that the method has industrial application potential. Furthermore, the obtained products can be used for producing ethylene glycol through hydrolyzing after hydrogenating or hydrogenating after hydrolyzing.

The invention relates to a method for synthesizing polyoxymethylene dimethyl ether, which mainly solves the problems of low reaction efficiency of a solid superacid catalyst, high cost of raw material trioxymethylene and more byproducts after reaction during synthesis of polyoxymethylene dimethyl ether existing in the prior art. In the method, dimethoxymethane and paraformaldehyde are used as rawmaterials, wherein the mass ratio of the dimethoxymethane to the paraformaldehyde is 0.5-10:1; the raw materials are in contact with the catalyst to generate catalytic reaction to prepare the polyoxymethylene dimethyl ether under the conditions of reaction temperature of 70-200 DEG C and reaction pressure of 0.2-6MPa; the amount of the used catalyst is 0.1-5.0 percent; and the used catalyst comprises the following components in percentage by weight: (a) 30-80 parts of molecular sieve carrier; and (b) 20-70 parts of solid superacid. Due to the technical scheme, the problems are solved well; and the method can be used for industrial production of the polyoxymethylene dimethyl ether.

The present invention discloses a method for synthesizing polyoxymethylene dimethyl ethers by ionic liquid catalysis. The method comprises synthesizing polyoxymethylene dimethyl ethers by using a functional acidic ionic liquid as catalyst and using methylal and trioxymethylene as reactant under a relative mild reaction condition. The invention has advantages of high catalyst activity and reaction conversion, simple reaction process, high operationability and controllability, as well as good product distribution and high raw material utilization ratio.

The invention relates to a catalyst for PODE (polyoxymethylene dimethyl ether) and mainly solves the problems of low catalyst activity and low selectivity in the process for synthesizing PODE from methanol, methylal and paraformaldehyde used as reaction raw materials in the prior art. According to the technical scheme, the catalyst for PODE is metal ion modified sulfonic acid type polystyrene cation exchange resin comprising a crosslinked polystyrene framework and a sulfonic acid group; the metals are selected from at least one of group IB and group IIB, so that the catalyst can be applied to industrial production of PODE.