Abstract: An improved process for removing crosslinked photoresist polymer from printed circuit boards which comprises contacting the printed circuit board with methylene chloride containing from about 5 to about 10 volume percent of a mixture of methanol and methyl formate. Each additive must be present at a minimum concentration of one volume percent. Stabilizers for the methylene chloride, such as epoxides, may be present at amounts no greater than about 0.5 volume percent.
Type:
Grant
Filed:
February 14, 1983
Date of Patent:
March 20, 1984
Assignee:
The Dow Chemical Company
Inventors:
Wesley L. Archer, Vicki A. Lynn, Susan M. Dallessandro
Abstract: A process of making nitroalkanes which comprises reacting a lower alkanol, e.g. methanol, and nitric acid (HNO.sub.3) in the vapor phase in the presence of a catalyst which is an oxide or a salt of a metal of Group II of the periodic table, e.g. calcium chloride.
Abstract: A process of making a high purity, low surface area porous alumina support having improved crush strength and abrasion resistance which comprises employing with the alumina a small amount of barium aluminate or silicate during its manufacture.
Abstract: An improved process for the vapor phase nitration of alkanes comprising feeding the alkane with an inert diluent gas and vaporizing the nitric acid on the surface of a catalyst bed which is the salt or oxide of a group II metal of the periodic chart.
Abstract: Trichloroethylene is stabilized against oxidation by adding a nitrogen-containing compound selected from among .alpha.-(dimethylamino) propionitrile, thiazole, 1-aza-2-alkoxy-1-cycloalkene and 1,5-diazabicyclo[5.4.0]undec-5-ene. These may be used in combination with ethyl acetate, acetonitrile and pyrazine.
Abstract: Partially chelated solutions of zinc have been prepared by employing ammonium salts of EDTA together with excess ammonia and dissolving therein an oxide or hydroxide of zinc.
Abstract: A stabilized chlorinated solvent composition useful in removing grease from metals wherein the solvent is perchloroethylene or trichloroethylene, and the stabilizer is N-methyl pyrrole in combination with ethyl acetate, acetonitrile or pyrazine.
Type:
Grant
Filed:
June 18, 1981
Date of Patent:
January 11, 1983
Assignee:
The Dow Chemical Company
Inventors:
Nobuyuki Ishibe, Jimmie K. Harden nee Ashley
Abstract: A method of preparing a supported catalyst of a gold-silver alloy useful for making ethylene oxide by applying a gold salt to a suitable support, reducing it to gold metal, then applying a silver salt and reducing it to silver, thereby forming a gold-silver alloy by diffusion, on the support.
Abstract: A process for making Fe-EDTA chelate comprising adding iron oxide at a ratio of <1 mole iron/mole EDTA to a mixture of NH.sub.4 OH and EDTA wherein NH.sub.3 /EDTA mole ratio is from 1 to not more than 1.5, heating until reaction is complete, cooling to about 60.degree. C. and adding sufficient NH.sub.3 to dissolve and maintain Fe-EDTA chelate in solution, cooling to room temperature and oxidizing Fe++ to Fe+++. The process provides (1) a minimum of foaming and sludge formation during the reaction, (2) rapid dissolution of iron oxide and (3) a chelate product substantially completely in the ferric state.
Type:
Grant
Filed:
September 8, 1980
Date of Patent:
December 21, 1982
Assignee:
The Dow Chemical Company
Inventors:
Katherine H. Svatek, David A. Wilson, Freddie Griffin, Jr.
Abstract: An improved process of making a silver catalyst which comprises impregnating a suitable support with an aqueous ammoniacal solution of a silver salt of an organic carboxylic acid and reducing said salt in the presence of a polyhydroxy compound.
Type:
Grant
Filed:
September 4, 1981
Date of Patent:
November 30, 1982
Assignee:
The Dow Chemical Company
Inventors:
Jeffry A. Solomon, Harold W. Young, Jr.
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 are:M.sub.10 Fe.sub.0.5-2.9 Cr.sub.0.3-1.7wherein M is tantalum or niobium.
Abstract: A method of purifying bisphenols by (1) crystallizing the crude bis from a single liquid phase containing water, bis and an organic solvent, (2) stripping the remaining mother liquor (containing the impurities) of solvent and water, and (3) mixing it with phenol, (4) contacting the mixture of phenol and mother liquor with a cation exchange resin to convert the impurity to the desired product, (5) stripping the phenol and (6) recycling the remainder to the initial crystallizing step.
Abstract: A stabilized methylchloroform for use in vapor degreasing which is stable in the presence of metals which contains pyrazine, dimethoxypropane, an acetylenic alcohol and a nitroalkane or a methylfuran. Such combination prevents corrosion of aluminum, iron, copper and zinc and the decomposition of the solvent.
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.
Type:
Grant
Filed:
October 17, 1979
Date of Patent:
September 21, 1982
Assignee:
The Dow Chemical Co.
Inventors:
David L. Childress, William V. Hayes, Richard L. Poppe
Abstract: A method of shipping liquid ethylene oxide in a manner which reduces the explosive hazard during shipment by combining the liquid ethylene oxide with at least 52% of liquid propylene oxide based on the total weight of the mixture. It is especially useful for bulk liquid shipment marine vessels and the ethylene oxide is easily separated from the mixture for use by a simple distillation.
Abstract: A stabilized methylchloroform solvent useful in degreasing operations in which the alkylene oxide stabilizer component normally employed is replaced by a tricyclic or quadricyclic compound containing a fused cyclopropane ring.
Abstract: Methylchloroform formulations are stable in the presence of zinc when they contain cyclopropyl methyl carbinol in place of an epoxide as a component of the stabilizer.
Abstract: The in situ production of hydrochloric acid in a subterranean formation to increase the flow of gas or oil therefrom by decomposing a polyhalohydrocarbon in the formation is accomplished at lower temperature by injecting the polyhalohydrocarbon together with isopropyl alcohol or a Lewis acid, e.g. FeCl.sub.3, or a mixture of the alcohol and Lewis acid.
Abstract: A process for making nitroalkanes in which an alpha-bromoalkanoic acid is reacted with an alkali metal nitrite, e.g. NaNO.sub.2, in the presence of the magnesium ion (Mg.sup.++) in an aprotic solvent to form a chelate. Neutralization of the chelate with a mineral acid produces a nitroalkane having one less carbon atom than the reactant bromoalkanoic acid.
Abstract: An improved process of preparing an aqueous solution of the zinc chelate of N-(2-hydroxyethyl) iminodiacetic acid wherein ammonia is added to the aqueous solution during its preparation to increase the solubility of zinc therein.
Type:
Grant
Filed:
March 31, 1980
Date of Patent:
January 26, 1982
Assignee:
The Dow Chemical Company
Inventors:
David A. Wilson, Druce K. Crump, Freddie Griffin, Jr.