Abstract: The invention relates to the manufacture of 1,1,1,2-tetrafluoroethane (F134a) by gas-phase catalytic fluorination of 1-chloro-2,2,2-trifluoroethane (F133a).A mixed catalyst is employed, composed of nickel and chromium oxides, halides and/or oxyhalides deposited on a support consisting of aluminium fluoride or of a mixture of aluminium fluoride and alumina.This mixed catalyst makes it possible to obtain an excellent selectivity for F134a with a high production efficiency.

Abstract: The invention relates to continuous production of 1,1,1-chlorodifluoroethane from 1,1,1-trichloroethane and hydrofluoric acid by reaction in liquid phase in the presence of at least one fluorination catalyst. According to the invention, the process is carried out under an absolute pressure of between 6 and 30 bars and at a temperature of between 50.degree. and 120.degree. C., the content of catalyst(s) in the reaction mixture, expressed as a percentage by weight of metal, being between 0.05 and 10% and the content of organohalogenated by-products not belonging to series 140 in the reaction mixture being controlled at a value below 40% by weight. This process makes it possible, at the same time, to obtain a high degree of conversion of hydrofluoric acid, to minimize the coproduction of 1,1,1-trifluoroethane and organohalogenated by-products and to facilitate the recovery of the hydrochloric acid formed.

Abstract: A drum is filled with two liquids of different densities which are immiscible when combined, such as white phosphorus and water. The drum is positioned on a scale beneath a fill pipe. An actuator lowers the fill pipe into the drum. A quantity of water is injected, followed by a quantity of white phosphorus, followed by a quantity of water to rinse the fill pipe. The fill pipe is raised just out of the liquids and allowed to drip, and then is fully raised to enable the filled drum to be replaced by an empty drum. The white phosphorus is injected at varying flow rates.

Abstract: To replace 1,1,2-trichloro-1,2,2-trifluoroethane (F113) in its applications to the cleaning and drying of solid surfaces, the invention propose to employ a (perfluoroalkyl)ethylene of formula:R.sub.f CH.dbd.CH.sub.2in which R.sub.f denotes a linear or branched perfluoroalkyl radical containing from 3 to 6 carbon atoms.In contrast to F113, (perfluoroalkyl)ethylenes are not liable to degrade stratospheric ozone.

Abstract: This invention relates to a process for the purification of 1,1-dichloro-1-fluorethane.To remove unsaturated impurities such as 1,1-dichloroethylene and dichloracetylene the crude 1,1-dichloro-1-fluoroethane is subjected to the action of chlorine and/or of a hydracid. This treatment is carried out in the presence of a Lewis acid, or, only in the case of chlorine, by photochemical catalysis.

Abstract: The invention relates to a process for the manufacture of 1,1,1,2-tetrafluorochloroethane and of pentafluoroethane.The process which consists of gas phase catalytic fluorination of at least one pentahaloethane of formula C.sub.2 HX.sub.2-n F.sub.3+n in which X denotes a chlorine or bromine atom and n the number 0 or 1, by hydrofluoric acid, is characterized in that a catalyst is employed consisting of a catalytic quantity of chromium in an oxidation state equal to or greater than 3 and of an activated charcoal as support.The selectivity for 1,1,1,2-tetrafluorochloroethane and pentafluoroethane reaches approximately 95% and even more.

Abstract: A process for preparing chemithermomechanical pulp comprising subjecting a lignocellulosic substance from which said pulp is to be formed to the simultaneous action of a sulfite and a reducing agent that is more electronegative than the sulfite ion during a nondestructive cooking operation at a temperature of about 100.degree. C. or above under saturated steam pressure; said simultaneous action taking place at an initial pH of between 7 and 12.5.

Abstract: For replacing cleaning compositions based on 1,1,2-trichloro-1,2,2-trifluoroethane (F113), the invention provides a composition comprising 55 to 80% by weight of 1,1-dichloro-1-fluoroethane (F141b) and 45 to 20% by weight of methyl formate. These two compounds form a positive azeotrope (b.p.=28.4.degree. C. at atmospheric pressure).The composition, which may be stabilized, can be used for cleaning solid surfaces, in particular for removing flux from printed circuits and for degreasing mechanical parts.

Abstract: To replace 1,1,2-trichloro-1,2,2-trifluoroethane (F113) in its applications to the cleaning and drying of solid surfaces, the invention propose to employ a (perfluoroalkyl) ethylene of formula:R.sub.f CH.dbd.CH.sub.2in which R.sub.f denotes a linear or branched perfluoroalkyl radical containing from 3 to 6 carbon atoms.In contrast to F113, (perfluoroalkyl)ethylenes are not liable to degrade stratospheric ozone.

Abstract: A composition is provided which is coextrudable with vinylidene polyfluoride permitting it to adhere to incompatible polymeric resins, the composition which has a base of an alkyl polymethacrylate and a thermoplastic polymer is comprised of:from 27 to 50 parts by weight of an alkyl polymethacrylate; andfrom 73 to 50 parts by weight of an additive itself constituted for 100 portions by weight of additive of:from 35 to 50 parts by weight of PVDF, andfrom 65 to 50 parts by weight of acrylic or methacrylic elastomer.This composition serves to produce vinylidene polyfluoride compounds capable of coating polymers which are non-compatible with vinylidene polyfluoride. When used as an adhesion agent, one can obtain by coextrusion, compounds of vinylidene polyfluoride and polymers non-compatible with the vinylidene polyfluoride.

Abstract: The catalysts according to the invention are mixtures of an antimony trihalide and of a titanium tetrahalide.These catalysts can be used for the liquid phase fluorination of halogenated aliphatic hydrocarbons, especially that of chlorinated ethane and ethylene derivatives.

Abstract: This invention proposes to employ a mixture of dimethyl ether and of 1,1,1,2-tetrafluoroethane as refrigerant fluids to replace chlorofluorocarbons.These compounds form an azeotrope which, at its normal boiling point (approximately -22.4.degree. C. at 1.013 bar), contains approximately 62.3 mass % of 1,1,1,2-tetrafluoroethane.The mixture according to the invention can also be employed as aerosol propellant or as blowing agent for plastic foams.

Abstract: Novel heat-sensitive recording media include a support substrate, e.g., paper or a synthetic polymer film, having a thermosensitive recording layer deposited thereon, such thermosensitive recording layer comprising a colorant precursor, a heat-sensitive developer therefor and at least one polyphenylmethane of the formula (A1): ##STR1## in which R.sub.1 and R.sub.2, which may be identical or different, are each a halogen atom, NO.sub.2, CN, OCH.sub.3, H or an alkyl radical having up to 5 carbon atoms; n is 3, 4 or 5; p is 1, 2 or 3; g is 0 or 1 and the maximum value of p+g is 2; and the melting point of which polyphenylmethane being at least 50.degree. C.

Abstract: Novel (naphthyloxy)benzoic/naphthoic acid compounds, polymerizable into thermotropic polymers have the formulae: ##STR1## in which R is hydrogen, a straight or branched chain aliphatic or cycloaliphatic hydrocarbon radical having from 1 to 4 carbon atoms or a radical ##STR2## wherein R' is a methyl or ethyl radical, or salt thereof.

Abstract: For replacing cleaning compositions based on 1,1,2-trichloro-1,2,2-trifluoroethane (F113), the invention provides a composition comprising 55 to 79.5% by weight of 1,1-dichloro-1-fluoroethane (F141b), 20 to 40% by weight of methyl formate and 0.5 to 5% of methanol. These three compounds form a positive azeotrope (b.p.=28.3.degree. C. at atmospheric pressure).The composition, which may be stabilized, can be used for cleaning solid surfaces, in particular for removing flux from printed circuits and for degreasing mechanical parts.

Abstract: The invention relates to the manufacture of chlorofluoroethanes of formula CF.sub.3 --CHF.sub.x Cl.sub.2-x, where x is equal to 0 or 1, by catalytic hydrogenation of a perhaloethane of formula CF.sub.3 --CF.sub.x Cl.sub.3-x.The use of an iridium-based catalyst deposited on a support enables the selectivity to be improved.

Abstract: The invention relates to polyfluoroalkyl nitrogen compounds of general formula:R.sub.F --(CH.sub.2).sub.2 --Xin which X denotes an isothiocynate --N.dbd.C.dbd.S, carbodiimide --N.dbd.C.dbd.N(CH.sub.2).sub.2 --R'.sub.F or thiourea --NH--CS--A group, A denoting an optionally substituted amino group, and each of the symbols R.sub.F and R'.sub.F denotes a perfluoroalkyl radical.These compounds, prepared from the corresponding azides R.sub.F (CH.sub.2).sub.2 N.sub.3 or amines R.sub.F (CH.sub.2).sub.2 NH.sub.2, can be used as surface-active agents or precursors of such agents.

Abstract: For replacing cleaning compositions based on 1,1,2-trichloro-1,2,2-trifluoroethane (F113), the invention provides a composition comprising 55 to 80% by weight of 1,1,1,2,2-pentalfuoro-3,3-dichloropropane (225ca) and 20 to 45% by weight of methyl tert-butyl ether.These two compounds form a negative azeotrope (b.p.=59.9.degree. C. at atmospheric pressure).The composition, which may be stabilized, can be used for cleaning solid surfaces, in particular for removing flux from printed circuits and for degreasing mechanical parts.

Abstract: The invention relates to an azeotrope with a minimum boiling point, capable of being employed as a refrigerating fluid replacing trifluorobromomethane (Halon 1301) in industrial refrigeration systems at very low temperature with single-stage compression.The azeotrope according to the invention is a mixture of 1,1,1-trifluoroethane (HFA 143a) and of propane (R290). At the normal boiling point (approximately -53.4.degree. C. at 1.013 bars), its 1,1,1-trifluoroethane content is approximately 70.6 mass % and that of propane 29.4 %.This azeotrope can also be employed as an aerosol propellant or as a blowing agent for plastic foams.

Abstract: The invention relates to compounds of the polyfluoroalkyl acetate, thioacetate or acetamide type, which can be denoted by the general formula: ##STR1## in which Rf denotes a perfluoroalkyl radical, m is an integer ranging from 1 to 4, Q denotes an oxygen or sulphur atom or an NH group, X.sup.- denotes an anion, R.sub.1 denotes an alkyl radical containing from 1 to 3 carbon atoms, R.sub.2 denotes the allyl radical or an alkyl radical containing from 1 to 18 carbon atoms, and R.sub.3 denotes an alkyl radical containing from 7 to 18 carbon atoms or one of the following radicals: ##STR2## wherein n is an integer from 2 to 4, R is hydrogen or methyl, and Y denotes C.sub.2 -C.sub.8 alkylene bridge optionally interrupted by an oxygen atom.These compounds can be used as surface-active agents or an monomers for developing artificial vesicles.