Abstract: An improved process for the photochlorination of normal paraffins to prepare mono-chlorinated alkanes, in which the normal paraffin feed stream is only partially chlorinated and the unreacted normal paraffins separated and recycled, the recycled unreacted paraffin being treated with a basic material capable of removing polar impurities therefrom which may hinder the photochlorination reaction.
Abstract: An improved process for preparing diaryl esters of dicarboxylic acids is disclosed, in which the esterification reaction is optimized by gradually increasing the temperature at which the reaction is being conducted according to a predetermined pattern. The temperature increase should be a function of the degree of esterification. The diaryl esters so prepared are useful in making linear polyesters.
Abstract: An improved process for preparing diaryl esters of dicarboxylic acids is disclosed, in which the esterification reaction is optimized by removing water and other by-products of the reaction according to a predetermined pattern. The removal of water and other by-products of the esterification reaction is most easily carried out by a distillation means, and the rate of removal is controlled by varying the reflux ratio in the distillation means during the course of the esterification reaction. The diaryl esters so prepared are useful in making linear polyesters.
Abstract: A process for removing dissolved chromium from a solution wherein said chromium is in the anion form which comprises contacting said solution with an adsorbent, comprising a hydrous oxide of iron at conditions whereby said chromium is adsorbed on said hydrous oxide, and wherein said hydrous oxide of iron is a granular, porous, high surface area, substantially non-crystalline, black material.
Abstract: A coating composition is provided which is suitable for the protection of corrodible metallic surfaces. The coating composition includes a binder and a filler, with the filler present in an amount sufficient to impart corrosion-resistant characteristics to the coating composition. The filler comprises conductive metal particles and particles of a metal composition which comprises silicon and at least one active metal. The metal composition can be an alloy of silicon with an active metal which is unstable when introduced alone into water or a silicide of an active metal which is unstable when introduced alone into water.
Abstract: High shielding efficiencies to emissions of electromagnetic interference are achieved with molding compositions comprised of thermosetting resins and a multi-component electroconductive filler system. Compounds having a combination of at least two conductive fillers provide shielding efficiencies of 30 dB of attenuation or more to electromagnetic emissions over a frequency range of 0.5 to 1000 Mhz without adversely affecting mechanical properties and processing capabilities.
Abstract: A method is provided for preventing the dissolution of transition metal-based cathodes used in chlor-alkali diaphragm cells by adding a small amount of a corrosion inhibitor, such as sodium silicate or trisodium phosphate, to the electrolytic solution during periods of interrupted current flow to the cell. The corrosion inhibitor is adsorbed on the surface of the cathode and forms an adherent protective film on the cathode. This film protects the cathode by preventing dissolution of the transition metal in the cathode coating due to oxidation by sodium hypochlorite.
Type:
Grant
Filed:
December 21, 1981
Date of Patent:
September 11, 1984
Assignee:
Occidental Chemical Corporation
Inventors:
Tilak V. Bommaraju, Krishnan Viswanathan
Abstract: Chloro-aromatic compounds of the formula ##STR1## wherein R is CF.sub.3, OCF.sub.3, OC.sub.2 F.sub.5, CN, NCO, or COCl, m is 0 or 1, and n is 0 or 1 are prepared by the vapor phase chloro-denitration reaction of a chlorinating agent with a nitro-aromatic compound of the formula ##STR2## where R, m, and n are as defined above.
Type:
Grant
Filed:
February 9, 1982
Date of Patent:
September 11, 1984
Assignee:
Occidental Chemical Corporation
Inventors:
David Y. Tang, Byron R. Cotter, Frederick J. Goetz
Abstract: Diphenyl esters of the formula ##STR1## wherein R is hydrogen, carboxy, carboxylate salt or ester, formyl, cyano, alkyl, alkoxy, chloro, bromo, or N, N-dialkyl amino, are prepared by reacting a chloro-fluoro-benzotrifluoride with a nitro-phenoxide of the formula ##STR2## where R is defined above, and M is a cation of an alkali metal or an alkaline earth metal.
Type:
Grant
Filed:
March 22, 1982
Date of Patent:
September 4, 1984
Assignee:
Occidental Chemical Corporation
Inventors:
David Y. Tang, Byron R. Cotter, Frederick J. Goetz
Abstract: A resin coated sand for shell-molding processes is provided comprising the coating of foundry sand or aggregates with a phenolic resin and a carboxylic acid salt. The carboxylic acid salt is selected from a carboxylic acid salt of an element selected from groups Ia, Ib, IIa, IIb, IIIa, IVa, Va, VIb, VIIa, VIIb or VIII of the Periodic Table of Elements. The proportion of carboxylic acid salt to phenolic resin is from 0.5 to 40 parts carboxylic acid salt to 100 parts phenolic resin. This resin coated sand produces shell-molds having excellent properties for casting, and allows the molded article to be removed in an easy and efficient manner.
Abstract: A method for the preparation of a 2-(trifluoromethyl)phenyl carbamic fluoride comprises isomerizing N-(trifluoromethyl)-anthraniloyl fluoride in the presence of hydrogen fluoride to 2-(trifluoromethyl)phenyl carbamic fluoride.
Abstract: Linear aromatic polyesters of bisphenols and dicarboxylic compounds are prepared by transesterification polymerization in either a fully continuous process or in a semi-continuous process wherein a first stage is conducted batchwise and a second stage is conducted in a continuous manner wherein the second stage employs a wiped film reactor, alternatively, a wiped film reactor followed by a vented extrusion reactor. The processes are preferably conducted in the presence of a catalyst in liquid form, and further under conditions wherein the catalyst is introduced to the polymerization concurrent with the introduction of liquid phase reactants to avoid substantial heating of the reactants in contact with the catalyst prior to onset of the transesterification reaction. The products of the processes have an unexpectedly low polydispersity.
Abstract: A resin coated sand for shell-molding foundry operations having improved shake-out properties for molds prepared therefrom is disclosed. Also disclosed are methods of producing said sand. The foundry aggregates or sand are coated with a phenolic resin containing from 0.2 to 40 parts of an aromatic nitro compound per 100 parts of phenolic resin. The resin may be a novolac type, a resole type or a mixture of the two types of phenolic resins. Suggested aromatic nitro compounds are nitrophenols, dinitrophenols and nitronaphthalenes. The process is extremely useful for coating lower melting temperature metals such as aluminum and magnesium.
Abstract: A process for preparing resin coated sand for shell molding foundry operations is disclosed wherein the resin utilized is a phenolic resin containing a bromophenol. The resin coated sand has improved shake-out properties and is especially formulated for low melting metals such as aluminum and magnesium castings.
Abstract: An improved resin coated sand for use in foundry shell-molding applications is disclosed which has increased resistance to thermal shock at the time of pouring. The improved product uses a phenolic resin as binder with aromatic compounds selected from the following generic formulae: ##STR1## wherein m, n, x and y are integers. The foundry aggregates are mixed with the phenolic resin and organic compounds under conventional mixing conditions to form a sand-resin mixture that can be formed into shell-molds. Upon casting the molten metal into these molds, the abrupt thermal expansion of the coated sand is controlled to eliminate the cracking that occurs when conventional phenolic-sand mixtures are employed.
Abstract: An improved resin coated sand for use in foundry shell-molding applications is disclosed which has increased resistance to thermal shock at the time of pouring. The improved product uses a phenolic resin as binder with aromatic compounds selected from the following generic formulae: ##STR1## The foundry aggregates are mixed with the phenolic resin and organic compounds under conventional mixing conditions to form a sand-resin mixture that can be formed into shell-molds. Upon casting the molten metal into these molds, the abrupt thermal expansion of the coated sand is controlled to eliminate the cracking that occurs when conventional phenolic-sand mixtures are employed.
Abstract: A process for the preparation of a resin-coated sand for use in shell-molding operations wherein the molding operation is designed for metals such as aluminum, magnesium and their alloys which have a lower-melting temperature than iron. The process involves the coating of foundry sand with a phenolic resin incorporating a carbonate and/or bicarbonate of elements selected from groups Ia, IIa, IIIb, IVb, Vb, VIb, VIIb or VIII. This process produces a resin-coated sand with improved shake-out properties of the casting molds.
Abstract: This invention is concerned with foundry binder compositions for alkaline aggregates such as reclaimed sand, Olivia sand, alumina sand, etc., which cure at ambient temperatures. The binder composition is composed of phenolic resins, polyisocyanates and a hydrogen chloride emitting substance upon hydrolysis. Curing of this composition is by gaseous amines. The hydrogen chloride emitting substance on hydrolysis is selected from the following: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 can be selected from: Hydrogen, Chlorine, alkyl, vinyl or alkoxy, or(b) Thionyl chloride, sulfuryl chloride, acid chlorides of sulfur, such as methyl chlorosulfuric acid, ethyl chloroculfuric acid.
Abstract: A novel thermoplastic polymer composition comprises a blend of a high impact vinyl halide polymer, particularly a vinyl halide-polyolefin graft polymer, and a copolymer of styrene and maleic anhydride and modifications thereof.