摘要:
A particularly useful process which includes the steps of providing a feedstream comprising providing a source of formaldehyde formed by conversion of dimethyl ether in the presence of a catalyst comprising tungsten oxide; and (i) heating the feedstream with the heterogeneous acidic catalyst in a catalytic distillation column to convert methanol and formaldehyde present to methylal and higher polyoxymethylene dimethyl ethers and to separate the methylal from the higher polyoxymethylene dimethyl ethers is disclosed, and/or (ii) contacting the source of formaldehyde and a predominately dimethyl ether feedstream with a heterogeneous, condensation promoting catalyst capable of hydrating dimethyl ether under conditions of reaction sufficient to form an effluent comprising water, methanol, formaldehyde, dimethyl ether, and polyoxymethylene dimethyl ethers is disclosed. Unreacted dimethyl ether is recovered from the effluent and recycled to the formation of polyoxymethylene dimethyl ethers. The resulting dimethyl ether-free liquid mixture is heated in the presence of an acidic catalyst to convert at least the methanol and formaldehyde present to polyoxymethylene dimethyl ethers. Advantageously, methylal and higher polyoxymethylene dimethyl ethers are formed and separated in a catalytic distillation column. By including in the column an anion exchange resin, an essentially acid-free product is obtained which can be used directly as a blending component, or fractionated, as by further distillation, to provide more suitable components for blending into diesel fuel.
摘要:
A method for producing inexpensively in a high yield a halogen-containing aromatic compound, particularly a halogen-containing aromatic compound incorporating therein a bromodifluoroalkyl group, and a halogen-containing naphthalene compound useful as a raw material for a resin excelling in heat resistance, chemical resistance and water repellency, and having a low dielectric constant and a low refractivity are provided. This invention relates to a method for the production of an aromatic compound (II) having a (CH2)nCX2Br group (wherein X represents a fluorine or chlorine atom and the X's may be same or different, and n is an integer in the range of 0 to 4) by the reaction of photo-bromination of an aromatic compound (I) having a (CH2)nCX2H group (wherein X and n are as defined above) with a brominating agent, wherein the photo-bromination reaction is carried out while removing hydrogen bromide generated in the reaction system and/or in an atmosphere of a low oxygen content, and a halogen-containing naphthalene compound represented by the following formula (1): wherein Y represents —CF2H, —CF2Br, or —CHO group, Z1 and Z2 independently represent a halogen atom, and p and q independently are an integer in the range of 0 to 3.
摘要:
Disclosed is process for the treatment of cyclopropanecarboxaldehdye (CPCA) which contains crotonaldehyde impurity with a base at elevated temperature to convert the crotonaldehyde to one or more higher boiling compounds followed by distillation to recover CPCA substantially free of crotonaldehyde. This selective reaction may be combined with a distillation to purify CPCA or in combination with the reaction of the CPCA in the treated mixture to produce a CPCA-derivative while avoiding or minimizing the formation of the analogous crotonaldehyde derivative.