Abstract: Aggregate-forming suspensions containing a coagulant therefor, e.g., FeCl.sub.3, polyaluminum chloride or Al.sub.2 (SO.sub.4).sub.3, are coagulated/flocculated by stirring to provide mechanically strong flocs of greater average diameter size, without concomitant formation of irreversible microflocs, and wherein the stirring regime, in at least the initial stage of coagulation/flocculation, includes an initial operating stirring cycle comprising (i) a rapid stirring sequence at an average velocity gradient ranging from 300 to 1,000 s.sup.-1 for a period of time ranging from 30 to 200 seconds, and (ii) a slow stirring sequence at an average velocity gradient ranging from 40 to 100 s.sup.-1 for a period of time ranging from 5 to 40 minutes.
Type:
Grant
Filed:
July 2, 1993
Date of Patent:
September 19, 1995
Assignee:
Elf Atochem S.A.
Inventors:
Jean-Yves Bottero, Bruno Lartiges, Herv' Suty
Abstract: Deinked paper/wood pulps are improvedly bleached to high levels of whiteness by conjointly treating such pulps with a sulfite bleaching agent, e.g., Na.sub.2 SO.sub.3, NaHSO.sub.3 or mixture thereof, or SO.sub.2 and NaOH, and a reducing agent more electronegative than the sulfite ion, e.g., thiourea dioxide, sodium borohydride or sodium dithionite, in a reaction medium having an initial pH ranging from 6 to 12, advantageously followed by washing sulfite and reducing agent values from the bleached pulp and then treating the washed pulp with hydrogen peroxide in an aqueous alkaline medium.
Abstract: A novel gas phase process for the production of 1,1-dichloro-1-fluoroethane from vinylidene chloride and hydrogen fluoride is provided. The process is characterized by high conversion of vinylidene chloride to product, with a high selectivity for 1,1-dichloro-1-fluoroethane. The process may also be operated to selectively form 1-chloro-1,1-difluoroethane. Few volatile by-products and substantially no tar or oligomeric material is formed. Catalyst performance remains constant over extended periods of time.
Abstract: Benzyltoluene/benzylxylene admixtures, easily prepared via Friedel-Crafts condensation of benzyl chloride with a mixture of toluene and xylene, are useful dielectric oils exhibiting improved rigidity and are well suited for inclusion in voltage transformers, capacitors, electrical cables, and the like.
Type:
Grant
Filed:
November 24, 1992
Date of Patent:
August 29, 1995
Assignee:
Elf Atochem S.A.
Inventors:
Raymond Commandeur, Pierre Jay, Noelle Berger
Abstract: Thermoplastic polyblend compositions, well suited for the production of mechanically strong and chemical-resistant shaped articles having a wide variety of chemical engineering and other applications, e.g., for the production of electrical cable for high-frequency electrical transmissions, comprise (i) a fluoropolymer, (ii) an aromatic polyester and (iii) a copolymeric compatibilizing agent therefor, the compatibilizing copolymer (iii) comprising the copolymerizate of ethylene, a glycidyl acrylate, an acrylic comonomer and, optionally, a peroxy comonomer.
Abstract: A process for producing a substantially pure organic trisulfide from mercaptan and sulfur (or high rank organopolysulfide) wherein the sulfur is reacted with mercaptan in the presence of a heterogeneous alumina-based catalyst, ammonium, alkali metal or alkaline earth metal modified silica-based catalyst, zinc-based catalyst or mixtures thereof, and recovering a product containing at least a major proportion of trisulfide.
Type:
Grant
Filed:
January 13, 1993
Date of Patent:
August 15, 1995
Assignee:
Elf Atochem North America, Inc.
Inventors:
Emmanuel F. Arretz, Glenn T. Carroll, Roger T. Clark
Abstract: Particulates of a superabsorbent partially, neutralized acrylic polymer, e.g., polyacrylic acid, having a mean particle size ranging from 100 to 500 .mu.m, essentially monodisperse and essentially devoid of fines having a particle size of less than 100 .mu.m, having a nonuniformly surfaced spheroidal particle morphology and containing less than 50 ppm of residual monomer, well suited for a variety of hygienic applications, are prepared by (i) polymerizing a suspension of an acrylic monomer charge I in an organic medium and producing a suspension of acrylic polymer gel particles, (ii) next absorbing a second acrylic monomer charge II into the gel particles, (iii) polymerizing in the gel particles the second acrylic monomer charge II, (iv) azeotropically dehydrating the acrylic polymer particulates thus obtained, (v) then treating the dehydrated particulates with hydrogen peroxide, and (vi) drying the superabsorbent particulates thus treated.
Type:
Grant
Filed:
September 13, 1994
Date of Patent:
August 15, 1995
Assignee:
Elf Atochem S.A.
Inventors:
Shu R. Rebre, Christian Collette, Sandrine Denie
Abstract: The flow rate of a high temperature fluid flowing through a conduit is measured by passing ultrasonic waves through the fluid. The ultrasonic waves are emitted from an emitter located at one side of the conduit and are received by a receiver located at an opposite site thereof. A first spacer is disposed between the receiver and the conduit, and a second spacer is disposed between the emitter and the conduit. The spacers isolate the receiver and emitter from the high temperatures and conduct the ultrasonic waves without changing the frequency thereof. A quick-release clamp clamps the emitter, receiver and spacers together against the conduit.
Abstract: A process for the manufacture of MgCl.sub.2.MgO with narrow granulometric distribution by treatment of hydrated MgCl.sub.2 with an alcohol followed by heat treatment after partial elimination of the alcohol, characterized in that the hydrated MgCl.sub.2 is suspended in the alcohol, and that the molar ratio of the alcohol to the hydrated MgCl.sub.2 is lower than the solutility ratio of these two substances at the temperature of the suspension. The resultant MgCl.sub.2.MgO can be employed as a support in catalytic components for the polymerization of olefins.
Abstract: Improved thermoplastic compositions adopted for easy conversion, e.g., by injection molding or extrusion techniques, into useful shaped articles having high flexibility, and good tear resistance and elasticity, include a polyetheramide, advantageously a polyetheresteramide, and a styrene/diene copolymer, e.g., a copolymer of styrene with butadiene or isoprene, notably a linear or branched chain styrene/butadiene/styrene or styrene/isoprene/styrene copolymer.
Abstract: Malodorous/foul smelling paper mill effluents are deodorized by treating same with an effective deodorizing amount, e.g., from 0.01% to 5% by weight thereof, of an alkyl or polyoxyalkylene ester of undecylenic acid, for example methyl undecylenate or a polyoxyethylene undecylenate having 8 or 10 ethylene oxide recurring structural units.
Abstract: Fluorine-containing copolymers for use in coating substrates or for incorporation thereinto in order to impart water- and oil-repellent properties thereto are provided, starting from the following monomers:a) a polyfluorinated alcohol ester with a monocarboxylic alkene acid;b) an amino-alcohol ester with a monocarboxylic alkene acid;c) vinyl monomer having an alkylcarboxylate or alkylether group.
Type:
Grant
Filed:
August 3, 1994
Date of Patent:
August 8, 1995
Assignee:
Elf Atochem
Inventors:
Marie-Jose Lina, Christian Collette, Jean-Marc Corpart, Andre Dessaint
Abstract: Water-containing mixtures of at least one hydrocarbon/halocarbon and hydrochloric acid, e.g., the methyl chloride feedstream in conventional process for the synthesis of chloromethanes, are desiccated by intimately contacting such mixtures with an effective drying amount of an essentially anhydrous drying agent that includes (i) a metal sulfate, chloride or perchlorate, or (ii) phosphorus pentoxide.
Abstract: N-benzyl-N-organo-substituted aminoalkanol is prepared by reacting benzyl chloride or substituted benzyl chloride with an organo-substituted aminoalkanol in the presence of a molar excess of the starting aminoalkanol and, optionally, water, and in the absence of a) an organic solvent for the reactants and b) alkali metal hydroxide. A portion of the excess aminoalkanol may be substituted with an alternative amine or dissolved alkali metal carbonate.
Abstract: The present invention relates to a heat-sealable and peelable film for polystyrene containers, consisting of at least one thin film comprising a mixture (a) of polystyrene and (b) of one or more copolymer(s) of ethylene and of acrylic derivatives.It also relates to a process for sealing a polystyrene container by means of said film and to the heat-sealed polystyrene container thus obtained.
Abstract: Propanone-1,3-disulfonic acid (acetone disulfonic acid) may be prepared by reacting chlorosulfonic acid with acetone preferably in the presence of a solvent for the reactants, such as methylene chloride, although a neat reaction is possible. The reactants and reaction conditions prior to separation should be substantially anhydrous, but water may be added after reaction to separate the product as an aqueous solution.
Abstract: In order to remove the olefinic impurities (in particular 1-chloro-2,2-difluoroethylene and polyfluoropropenes) present in crude 1,1,1,2-tetrafluoroethane (F134a), a gaseous mixture of crude F134a, hydrofluoric acid and oxygen or air is treated in the gas phase, in the presence of a fluorination catalyst, at a temperature between 200.degree. and 350.degree. C. and at a pressure between atmospheric pressure and 2.5 MPa, the HF/F134a molar ratio being between 0.05 and 0.5 and the O.sub.2 /F134a molar ratio being between 0.001 and 0.1.
Type:
Grant
Filed:
October 26, 1994
Date of Patent:
July 4, 1995
Assignee:
Elf Atochem, S.A.
Inventors:
Bernard Cheminal, Andre Lantz, Eric Lacroix
Abstract: The invention relates to the separation of hydrogen fluoride (HF) from its mixtures with 1,1,1-trifluoro-2-chloroethane (F133a).By settling of the mixture of HF and F133a in the presence of trichloroethylene at a temperature below 0.degree. C., a lower organic phase which is poor in HF and an upper phase which is rich in HF are obtained. The latter can be directly recycled to the fluorination reactor or subjected to a distillation in order to separate, at the head, the HF/F133a azeotrope which is returned to the settler, and to recover, at the foot, practically pure HF. By distillation of the lower phase, the HF/F133a azeotrope which is returned to the settler is separated at the head and a mixture of F133a and trichloroethylene is recovered at the foot. The latter mixture is subjected to a distillation which makes it possible to separate, at the head, pure F133a from trichloroethylene at the foot.
Abstract: Tertiary-butyldiethanolamine subject to color deterioration is purified and stabilized against color formation by vacuum distilling said amine at a pressure within the range of 1 to 50 mm.
Abstract: The present invention relates to new polyamides comprising, on a mass basis:(a) 45 to 75% of an x,T unit, x being between 4 and 12 inclusive, the x,T unit being the condensation product of a diamine having x carbon atoms and of terephthalic acid, and(b) 55 to 25% of an aliphatic unit -HN-(CH.sub.2).sub.n -CO, n being between 6 and 14 inclusive. and the terpolyamides obtained by including a monomeric unit (c) such as the unit 6 or 6,I as a replacement for part of the aliphatic unit (b).The polyamide compositions thus obtained exhibit a Tg lower than 130.degree. C., a Tm higher than 230.degree. C. and a good crystallizability.
Type:
Grant
Filed:
December 30, 1992
Date of Patent:
June 6, 1995
Assignee:
Elf Atochem S.A.
Inventors:
Philippe Maj, Jean-Marc Sage, Philippe Blondel, Didier Judas