摘要:
Disclosed is a method and solvent composition capable of removing iron oxide deposits from the surface of titanium components without substantially damaging the underlying titanium component. Iron oxide deposits may be removed from the surface of a titanium component by contacting the titanium component with the solvent composition of the invention. The solvent composition may then be removed from contact with the titanium component to obtain a recyclable solvent composition which is recycled into repeated contact with the titanium component. The solvent composition comprises an aqueous mixture of an organic acid and a hydrohalide acid.
摘要:
Disclosed is a method and solvent composition capable of removing iron oxide deposits from the surface of titanium components without substantially damaging the underlying titanium component. Iron oxide deposits may be removed from the surface of a titanium component by contacting the titanium component with the solvent composition of the invention. The solvent composition may then be removed from contact with the titanium component to obtain a recyclable solvent composition which is recycled into repeated contact with the titanium component. The solvent composition comprises an aqueous mixture of an organic acid and a hydrohalide acid.
摘要:
A process for oxidation with oxygen of at least one aromatic hydrocarbon having oxidizable, substituents that maximizes the utilization of oxygen without reduction in the quality of the carboxylic acid products produced by means of a stagewise countercurrent oxidation system is disclosed.
摘要:
Processes for the production of aromatic carboxylic acids is disclosed. The aromatic acids are produced by the liquid phase oxidation of a suitable acid precursor in a reaction medium comprising benzoic acid. According to one embodiment, the oxidation is carried out under plug-flow reaction conditions in a plug-flow reactor. The plug-flow conditions can be achieved by the use of a series of continuous stirred tank reactors. In another embodiment, the oxidation is carried out in two continuous stirred tank reactors fluidly connected in series. The preferred oxidation products are terephthalic acid, isophthalic acid, trimellitic acid, 2,6-naphthalene dicarboxylic acid, 1,5-napthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid and phthalic acid.
摘要:
Economical processes are disclosed for preparing relatively pure polycarboxylic acid from typical crude products of liquid phase oxidation, which do not involve intermediate steps of ester formation or require any alkanol containing solvent, for purification of "crude" polycarboxylic acid containing impurities which include one or more monofunctional aromatic compounds, trifunctional aromatic compounds, and/or color causing organic compounds formed by oxidation of a corresponding substituted aromatic compound in a liquid phase, e.g. 2,6-naphthalene dicarboxylic acid by liquid phase oxidation of 2,6-dimethyl naphthalene. The invention provides integrate processes which comprise reacting crude oxidation product with a polyalkyl amine amine, e.g. trialkylamine, forming an aqueous solution of the salts thus obtained, separating deleterious compounds from the solution, and recovering the polyalkyl amine and a relatively pure polycarboxylic acid product.
摘要:
A method for the acid catalyzed cyclization of an alkenylbenzene feedstock to a dimethyltetralin in a liquid phase reaction wherein the desired dimethyltetralin is removed from the reaction mixture by distillation simultaneously with the addition of the feedstock to the reaction mixture.
摘要:
A catalytic process is provided for the selective production of pseudocumene and durene by contacting a hydrocarbon feed containing benzene or a methyl substituted benzene under methylating conditions and in the presence of a methylating agent with a catalyst comprising AMS-1B crystalline borosilicate. In the resulting product pseudocumene and durene are obtained in selectivities higher than equilibrium concentrations of respectively trimethylbenzenes and tetramethylbenzenes.
摘要:
Disclosed is a method for preparing an aromatic carboxylic acid comprising oxidizing in the liquid phase an aromatic feed compound containing at least one alkyl or acyl group with a molecular oxygen-containing gas, in a solvent comprising a low molecular weight aliphatic carboxylic acid, and in the presence of a heavy metal oxidation catalyst, thereby forming an oxidation reaction product mixture comprising an aromatic carboxylic acid; subsequently heating the oxidation reaction product mixture at a temperature of at least about 500.degree. F. to form a second product mixture; and recovering from the second product mixture the aromatic carboxylic acid. The method of this invention provides for purer, larger particle size aromatic carboxylic acid product.
摘要:
A method for preparing one or more specific dimethyltetralins from either 5-(o-, m-, or p-tolyl)-pent-1-or -2-ene or 5-phenyl-hex-1- or -2-ene, and optionally for preparing one or more specific dimethylnaphthalenes from the aforesaid dimethyltetralins is disclosed.
摘要:
A method is provided for cyclizing an alkenylbenzene to a dialkyltetrahydronaphthalene (dialkyltetralin) in the presence of a solid cyclization catalyst constituted by a relatively low acidity, ultrastable, hydrogen form of crystalline aluminosilicate zeolite Y having a sodium oxide-to-alumina bulk molar ratio in the range of about 0.001 to about less than 1, a unit cell size no greater than about 24.3 Angstroms, and a sodium content of no more than about 0.4 percent by weight, calculated as elemental sodium and based on the weight of the zeolite. This catalyst provides more activity, more stability, higher product purity, and higher product yields than known prior art zeolite cyclization catalysts notwithstanding its relatively lower acidity. A preferred alkenylbenzene is 5-(o-tolyl)-pent-2-ene which is converted in relatively high yields and relatively high selectivities to 1,5 dimethyltetrahydronaphthalene.