Abstract: A system and method for producing polyoxymethylene dimethyl ethers (DMMn) using an aqueous formaldehyde solution as the initial reaction material. The process system has a polymerization reaction unit, an acetalation unit, a product separation unit, and a catalyst regeneration unit. Both polymerization and acetalation reaction are conducted in the presence of an ionic liquid as a catalyst, which can achieve the effect that two different reactions may be catalyzed by the same ionic liquid. The present invention employs a simple catalyst system, and achieves the efficient separation of the catalyst, the byproduct water, the product and the reaction materials in a separation manner combining the extraction and the rectification.

Abstract: The invention relates to a reaction system and process for continuously preparing polymethoxy dimethyl ether (DMM3-8) by a continuous acetalization reaction between an aqueous formaldehyde solution or paraformaldehyde and methanol in the presence of a functionalized acidic ionic liquid as a catalyst. The reaction system of the invention preferably comprises a formaldehyde-concentrating unit, a vacuum-drying unit, an acetalization reaction unit, a product-separating unit and a catalyst-regenerating unit. The process of the invention uses aqueous formaldehyde solution as an initial raw material, which is concentrated in the formaldehyde-concentrating unit to a concentrated formaldehyde of 50˜80 wt. %, and vacuum-dried to paraformaldehyde, or uses paraformaldehyde as raw material directly, then obtains DMM3-8 by an acetalization reaction.

Abstract: A reaction system and method for producing polyoxymethylene dialkyl ethers (RO(CH2O)nR, n=1-8) by continuous acetalation of formaldehyde and aliphatic alcohol in the presence of an acid ionic liquid catalyst. The reaction system includes an acetalation reaction unit, a product separation unit, and a catalyst regeneration unit. The recyclable material and catalyst are separated by combining extraction and rectification, and a recovery rate of more than 99% for the catalyst is achieved. Water, as the byproduct, is separated from the reaction system by destroying the azeotrope of water, alcohol, aldehyde, and RO(CH2O)nR, so that the product separation and catalyst regeneration are facilitated and the catalytic cycle is achieved.

Abstract: The invention relates to a reaction system and process for continuously preparing polymethoxy dimethyl ether (DMM3-8) by a continuous acetalization reaction between an aqueous formaldehyde solution or paraformaldehyde and methanol in the presence of a functionalized acidic ionic liquid as a catalyst. The reaction system of the invention preferably comprises a formaldehyde-concentrating unit, a vacuum-drying unit, an acetalization reaction unit, a product-separating unit and a catalyst-regenerating unit. The process of the invention uses aqueous formaldehyde solution as an initial raw material, which is concentrated in the formaldehyde-concentrating unit to a concentrated formaldehyde of 50˜80 wt. %, and vacuum-dried to paraformaldehyde, or uses paraformaldehyde as raw material directly, then obtains DMM3-8 by an acetalization reaction.

Abstract: 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.

Abstract: 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.

Abstract: A system and method for producing polyoxymethylene dimethyl ethers (DMMn) using an aqueous formaldehyde solution as the initial reaction material. The process system has a polymerization reaction unit, an acetalation unit, a product separation unit, and a catalyst regeneration unit. Both polymerization and acetalation reaction are conducted in the presence of an ionic liquid as a catalyst, which can achieve the effect that two different reactions may be catalyzed by the same ionic liquid. The present invention employs a simple catalyst system, and achieves the efficient separation of the catalyst, the byproduct water, the product and the reaction materials in a separation manner combining the extraction and the rectification.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention relates to a process for synthesizing trioxymethylene, wherein an aqueous solution of formaldehyde is used as the reactant; and an acidic ionic liquid in an amount of from 0.01 to 10 wt % is used as a catalyst.

Abstract: The present invention relates to a process for synthesizing trioxymethylene, wherein an aqueous solution of formaldehyde is used as the reactant; and an acidic ionic liquid in an amount of from 0.01 to 10 wt % is used as a catalyst.