Abstract: A method of removing acrylic acid polymer from processing vessels, e.g., distillation towers, which comprises contacting said polymer with a dialkyl phthalate in vapor or liquid form at elevated temperatures. This procedure dissolves and depolymerizes the polymer and removes it from the vessel.
Abstract: A dehydration catalyst and process for making an alkylenimine from an alkanolamine wherein the catalyst contains oxides of either tantalum or niobium together with the oxides of iron and chromium and in which the ratios of the metals areM.sub.10 Fe.sub.0.5-2.9 Cr.sub.0.3-1.7wherein M is tantalum or niobium.
Abstract: The use of methylene chloride as a blowing agent for resinous foams, particularly urethane foams is improved by incorporating a low molecular weight polyhydroxy aliphatic compound having more than two hydroxyl groups. Simultaneously with the addition the amount of gelling catalyst (e.g., stannous octoate) required to obtain good foam, particularly the very soft foams, is reduced over that required using the methylene chloride without the addition of the polyhydroxy compound. Similarly, when the polyhydroxy compound of this invention is used, smaller amounts of the gelling catalyst are employed for equal foam properties when the fluorinated halocarbons are employed either alone or in combination with the methylene chloride.
Type:
Grant
Filed:
December 26, 1979
Date of Patent:
April 28, 1981
Assignee:
The Dow Chemical Company
Inventors:
Olga L. Milovanovic, Wolf Sehr, Richard S. Sayad
Abstract: An improved process for preparing a silver catalyst which comprises impregnating a porous alumina support with a silver salt, preferably silver nitrate, by contacting a quantity of the support with an aqueous solution of the salt in sufficient amount to be completely absorbed by said support while under a vacuum. A dispersing agent is also employed in the aqueous silver salt solution. The support is dried by heating, e.g. 100.degree. C., under vacuum and then, while still under vacuum, impregnated with a reducing agent employing an amount sufficient to be completely absorbed by the support. Subsequent heating at a higher temperature, e.g. 250.degree. C., reduces the silver salt to silver metal. A catalyst is produced which, when employed for the oxidation of ethylene, permits the process to run 5.degree.-10.degree. C. cooler at the normal conversion and also gives an improved yield.
Type:
Grant
Filed:
May 29, 1979
Date of Patent:
February 3, 1981
Assignee:
The Dow Chemical Company
Inventors:
Walter L. Wernli, William E. Fry, Steve F. Janda
Abstract: An improved process for obtaining bisphenols by reaction of a phenol, or substituted phenol having a hydrogen in the para position, and an alkenyl ether, wherein the unsaturation in the ether is in the alpha position, in the presence of a strong acid catalyst. The process gives particularly good results when bisisopropenyl ether is reacted with phenol in the presence of a strong acid cation exchange resin in which part of the exchange sites have been neutralized with 2,2-dimethylthiazolidine.
Abstract: Alkylene glycols are produced from alkylene carbonates by hydrolysis in the presence of water at temperatures of from about 80.degree. to about 200.degree. C. Catalysts, such as alumina, are employed at temperatures from 80.degree. to about 150.degree. C. and only slightly greater than the stoichiometric amount of water is employed to allow the most efficient use of the process.
Abstract: An improved process for making ethylene carbonate wherein ethylene oxide and carbon dioxide are passed over an anion exchange resin catalyst and wherein the ethylene oxide and carbon dioxide reactants are absorbed from the effluent of an ethylene oxide reactor, desorbed and used as feed to the ethylene carbonate plant without further purification.
Abstract: In the manufacture of ethylene oxide by the partial oxidation of ethylene in the vapor phase, the effluent gases from the reaction are absorbed in water prior to separation and purification of the ethylene oxide. The present invention is the improvement in which ethylene carbonate is employed as the absorbing medium for the ethylene oxide.
Abstract: A method for preparing acrylic acid by oxidation of acrolein over a new and improved catalyst providing conversions of acrolein of greater than 99% with yields of acrylic acid in excess of 95%. The catalyst consists essentially of the oxides of molybdenum, vanadium, chromium, copper and titanium and optionally silicon on an inert carrier. Catalysts useful in the process contain the elements previously mentioned in the atomic ratios ofMo.sub.15 V.sub.5-10 Cu.sub.2-5 Cr.sub.0.2-2 Ti.sub.1-3.
Type:
Grant
Filed:
October 26, 1978
Date of Patent:
June 17, 1980
Assignee:
The Dow Chemical Company
Inventors:
David L. Childress, William V. Hayes, Richard L. Poppe
Abstract: New copolymers have been made by reacting a divinyl aromatic compound, e.g., divinyl benzene, with primary or secondary amines, e.g., alkylene diamines or aromatic amines in the presence of a non-hydroxyl strong base, e.g., sodium amide. The reaction may be conducted neat or in an aprotic solvent such as tetrahydrofuran at ambient temperature.The copolymers may be quaternized with alkyl and aralkyl chlorides to give products which are useful algaecides and bactericides. The copolymers themselves can be used in detergents since they have surfactant properties.
Abstract: An improved process for making an alcohol by hydration of an olefin in the presence of a cation exchange resin in the acid form as catalyst and in the presence of a solvent for the reactants and product alcohol, wherein the solvent and reactants are introduced to the reactor as a single homogeneous phase to a first-stage reactor. Part of the olefin is added to a second-stage reactor. The effluent from the second stage is passed to a third-stage reactor and the unreacted olefin and solvent from the third-stage effluent are recycled to the first-stage reactor after removal of substantially all of the product alcohol. The process provides improved conversions and yields and enables the use of smaller amounts of solvent.
Type:
Grant
Filed:
July 11, 1977
Date of Patent:
January 8, 1980
Assignee:
The Dow Chemical Company
Inventors:
James H. Giles, Jeffery H. Stultz, Sandra W. Jones
Abstract: A method for reducing losses due to reactions between hydrogen halides and olefinically unsaturated organic compounds in the presence of transition metals which act as catalysts for hydrohalogenation in mixtures containing same by adding to said mixtures a compound selected from the class consisting of alkyl diketones. The present invention is of particular value in the separation of components of said mixtures by distillation, but may also be usefully employed in any operation in which these mixtures are maintained in the presence of said catalytic materials. The present method offers advantages over the prior art because of the relative low toxicity and flammability of diketones and the fact that no undesirable solids are formed to foul process equipment as with some known methods.
Abstract: A protective curable coating containing a polymerization inhibitor, extractable from the cured coating, which is applied to surfaces located above the liquid level of a storage tank containing a polymerizable alkenyl aromatic monomer, e.g., styrene, vinyl toluene, divinyl benzene on which surfaces said monomer tends to condense. The monomer condensing on the surfaces which have been coated extracts some of the inhibitor from the coating and thus polymerization on these surfaces is prevented or substantially restricted.
Abstract: A process for recovering substantially dry methyl chloride from a stream of wet methyl chloride by distilling the wet methyl chloride in the presence of at least 10 molar % hydrogen chloride based on the hydrogen chloride, methyl chloride and water being distilled. The distillation is carried out under super atmospheric pressure and a temperature to produce an aqueous hydrochloric acid of less than 36 wt %, and preferably under such super atmospheric pressure and sufficient temperature to produce an azeotropic hydrochloric acid containing a low concentration of hydrogen chloride. Increasing pressures allows increasing temperatures in the bottoms which form azeotropes of lower concentration hydrochloric acid. The resulting overhead of such a distillation, methyl chloride-hydrogen chloride, will contain less than about 400 molar ppm water. When the distillation is carried out in the presence of about 12 to 25 molar % hydrogen chloride, the overhead will contain between about 100 to 400 molar ppm water.
Type:
Grant
Filed:
July 8, 1974
Date of Patent:
March 20, 1979
Assignee:
The Dow Chemical Company
Inventors:
John M. Steele, Guillermo J. Nino, Fredric M. Hanak
Abstract: A process for recovering monomeric glycols and glycerine from polyoxyalkylene glycols and polyglycerines which comprises heating the polymeric compounds together with a lower saturated mono-carboxylic acid, containing from 2 to 4 carbon atoms such as acetic acid, in the presence of a strong acid, e.g. sulfuric acid, or a strong acid cation exchange resin. The product, which is the diester of the monomeric glycol or the triester of glycerine, is recovered and subsequently hydrolyzed to obtain the desired monoglycol or glycerine product. If it is desired to obtain the ester itself, the latter step of hydrolyzing can be omitted.
Type:
Grant
Filed:
June 18, 1976
Date of Patent:
May 2, 1978
Assignee:
The Dow Chemical Company
Inventors:
Fred A. Sherrod, William L. Howard, Joanne D. Burger