Showing papers by "Rhône-Poulenc published in 1986"

Pesticidal method using N-phenylpyrazoles

Abstract: A method for the control of arthropod, plant nematode or helminth pests using compounds of formula (I), wherein Y is halogen, cyano, nitro, RSO2, RSO or RS in which R is alkyl, cycloalkyl or alkenyl, thiocyanato, sulphamoyl, carbamoyl, alkoxycarbonyl, alkanoyl or alkyl; Z represents hydrogen, an amino group -NR1R2, alkylsulphenylamino, alkoxymethyleneamino, halogen, alkyl, carboxy, alkylthio, alkylsulphinyl or alkylsulphonyl, trialkylsilylmethyl, trialkylsilyl, cyano or nitro; R3 represents halogen, alkyl or alkoxy, halogen-substituted alkylthio or alkylsulphinyl, nitro, cyano, or alkylsulphonyl; and R4 represents halogen, cyano, nitro, alkyl or cycloalkyl, and n is 1 to 5, and salts thereof, provided that R4, Y and Z do not simultaneously represent one of nitro, cyano, halogen and unsubstituted alkyl; persticidal compositions, novel compounds and processes for their preparation are described.

Process for the hydrogenation of acetic acid

Abstract: Acetic acid is hydrogenated in vapour phase to produce ethanol in free form or in the combined form of ethyl acetate. The catalytic process now found takes place in relatively moderate temperature and pressure conditions, with a view to producing ethanol and/or ethyl acetate, and is characterised in that the catalyst consists of ruthenium deposited on a silica support. A process for manufacturing the catalyst is also claimed.

Design of high energy intermediate analogues to study sterol biosynthesis in higher plants.

Abstract: Several enzymes of plant sterol biosynthesis involve during their catalysis postulated or demonstrated carbocationic high energy intermediates (HEI). The aim of this study was to interfere with plant sterol biosynthesis by means of rationally designed species able to mimic these carbocationic HEI. It has been demonstrated previously that the design of transition state (TS) or HEI analogues could lead to powerful and specific inhibitors of enzymes. We applied this approach to the following target enzymes: 2,3-epoxy-2,3-dihydroqualene cyclase, AdoMet-cycloartenol-C-24-methyltransferase (AdoMet CMT), cycloeucalenol-obtusifoliol isomerase (COI) and Δ8-Δ7-sterol isomerase. Very potent inhibitors have been obtained in the four cases. As an example, analogues of cycloartenol substituted at C-25 by a charged heteroatom (N, As, S) have been synthesized and shown to be able to mimic the C-25 carbocationic HEI involved in the reaction catalyzed by the AdoMet CMT. These compounds were shown to be very potent and specific inhibitors of this enzyme both in vitro (Ki=2.10−8 M, Ki/Km=10−3) and in vivo. The potent inhibitors described are powerful tools to control in vivo the sterol profile of plant cells and therefore to study the structural and functional roles of sterols in cell membranes. Moreover, these compounds constitute leader molecules of a new class of rationally designed inhibitors which could be of value in plant protection.

Pharmacokinetics of pefloxacin after repeated intravenous and oral administration (400 mg bid) in young healthy volunteers

Abstract: Multiple-dose kinetics of pefloxacin was determined in 12 normal male subjects given 400 mg pefloxacin by iv 1 h-infusion every 12 h for 16 doses. Twelve other subjects (6 men and 6 women) were given 400 mg pefloxacin by mouth every 12 h for 18 doses. Plasma and urine concentrations of pefloxacin and its main metabolites (N-desmethyl pefloxacin or norfloxacin and pefloxacin N-oxide) were measured by high performance liquid chromatography. The bioavailability of pefloxacin was complete and plasma concentrations after iv or oral administration were similar. Pefloxacin was rapidly absorbed from the gastrointestinal tract and reached maximum plasma concentrations about 1 h after dosing. Pefloxacin elimination (T 1/2 beta) increased from 11.00 +/- 2.64 h after the first iv dose to 13.93 +/- 3.58 h after the last iv dose (P less than 0.01). Apparent total body clearance decreased from 148.5 +/- 47.6 to 106.9 +/- 39.2 ml/min (P less than 0.01) because of decreased non-renal clearance (apparent volume of distribution did not significantly change over the repeated pefloxacin administration). Similar results were obtained after repeated oral dosing. Renal clearance of pefloxacin was low (7.47 +/- 2.28 ml/min) indicating that non-renal clearance represents the major route of elimination of this quinolone. Urinary excretion of pefloxacin and N-desmethyl and N-oxide metabolites was approximately 31% of the pefloxacin dose and beta-elimination half-lives of these metabolites were very close to that of pefloxacin (13.34 +/- 2.72 h and 11.95 +/- 2.64 h respectively). Due to a possible saturable process in the metabolic pathway, some accumulation occurred during repeated iv or oral treatment (accumulation ratio = 1.37 +/- 0.20). These results show that concentrations of pefloxacin in excess of the minimum inhibitory concentrations for many important pathogens can be rapidly achieved in plasma and urine with the 400 mg bid regimen with both iv and oral routes.

Cerium/rare earth polishing compositions

Abstract: Glass polishing compositions, advantageously recycled into glassmaking formulations, are comprised of suspension of particulate ceric oxide and at least one colorless oxide of a lanthanide or yttrium rare earth, preferably an oxide of lanthanum, samarium, europium, gadolinium, dysprosium, thulium, ytterbium, lutecium, yttrium, or mixtures thereof.

Compositions for the preparation of microparticles by extrusion for the sustained release of biologically active substances, and microparticles so obtained

Abstract: 1. A composition for the preparation by extrusion of microparticles permitting a prolonged release of a biologically active substance, which composition consists of a biologically active substance, one or more non-hydrophilic polymers and from 10 to 40% by weight either of a mixture of at least two lipid excipients one of which has the property of dissolving or gelling the polymer or polymers and the other has lubricating properties or of a lipid excipient having both the property of dissolving or gelling the polymer or polymers and lubricating properties, and, if appropriate, one or more additives chosen from diluents and antistatic agents.

Use of coloured pigments based on rare earths sulphurs in plastics, paints, or vanishes

Abstract: 1. Use as coloured pigments of at least one sulphide of rare earths corresponding to the formula Ln2 S3 in which Ln represents at least one element from the group formed by lanthanides and yttrium in thermoplastic or thermosetting plastics materials, special polymers, in resins used as a component of paints and glazes, in nail varnishes and make-up materials used in cosmetology.

Cerium iv compound and method for its preparation

Abstract: 1. A compound of cerium IV corresponding to the following general formula (I) : Ce (M)x (OH)y (NO3 )z wherein : - M represents an alkali metal or a quaternary ammonium radical, - x is between 0.01 and 0.2, - y is such that y = 4 - z + x and - z is between 0.4 and 0.7.

Homogeneous, flexible block copolyetheramide having oxyalkylene units

Abstract: Novel, homogeneous and flexible block copolyetheramides, having a melting point of at least 150° C., a glass transition temperature not exceeding -5° C. and a melt viscosity of at least 100 poises, are preferably prepared by prepolymerizing a mixture of a salt of a short-chain aliphatic dicarboxylic acid and a short-chain aliphatic diamine with a fatty acid(s) dimer or amino derivative thereof, and then polycondensing the prepolymer in the presence of a strong organic or inorganic oxyacid, with a polyoxyalkylenediamine or a polyoxyalkylenedicarboxylic acid having a number-average molecular weight ranging from 300 to 1200.

Gel-forming aqueous microemulsions for soil stabilization

Abstract: Stable, gel-forming aqueous microemulsions, well adopted for the reversible stabilization or plugging of soil/rock formations, e.g., subterranean well formations, are comprised of (i) an aqueous solution of a water-soluble alkali metal silicate, (ii) a gelling reagent therefor, and (iii) at least one surface active agent.

Composition containing ceric oxide, its preparation and its use

Abstract: The invention permits the specific surface of a ceric oxide-based composition to be stabilised at high temperature. … The invention also relates to its preparation and its applications especially in the field of catalysis.

Transfer kinetics of pefloxacin into cerebro-spinal fluid after one hour iv infusion of 400 mg in man

Abstract: Nine subjects (5 women) aged between 17-66 years, with hydrocephalus were studied. An external ventricular drain was introduced for diagnostic purposes. Cerebro-spinal fluid (CSF) and plasma samples were obtained at suitable intervals after 1 h infusion of 400 mg pefloxacin. In plasma, pefloxacin Cmax was 8.54 +/- 1.53 (mean +/- S.E.M.) mg/l, at the end of infusion, whereas N-desmethyl pefloxacin concentration was 0.17 +/- 0.03 mg/l. The metabolite accounted for only 2% of plasma levels of pefloxacin. In CSF, pefloxacin Cmax was 2.97 +/- 0.32 mg/l, 5-6 h after the start of infusion, whereas N-desmethyl pefloxacin Cmax varied between 0.1-0.2 mg/l. Apart from the 1 h sample, the CSF/plasma ratio of pefloxacin was 60% which is similar to the unbound fraction of pefloxacin in plasma. The apparent half-life (T1/2) of transfer of pefloxacin from plasma to CSF was 1.26 +/- 0.18 h, assuming a first order process, while the apparent elimination T1/2 in CSF was 13.40 +/- 1.76 h, which is similar to the elimination T1/2 found previously in plasma, thus accumulation of pefloxacin in CSF is unlikely. With the present dosage regimen, CSF quickly attains therapeutic levels of pefloxacin.

Polysilazane composition which can crosslink in the presence of a metal compound catalyzing a hydrosilylation reaction

Abstract: A crosslinkable composition comprising at least one polysilazane containing at least 2, preferably at least 3, .tbd.SiH groups per molecule and at least 2 SiR 2 groups per molecule, R 2 being an unsaturated hydrocarbon radical and a catalytically effective quantity of a metal element or of a metal compound to catalyze the hydrosilylation reaction SiH/SiR 2 . The compositions according to the invention can crosslink under the effect of heat and can be used for coating or impregnating substrates with ceramic material after pyrolysis. The mechanical properties of the crosslinked compositions are assessed by evaluating the relative rigidity RR measured by the fiber torsion pendulum method (FIG. 1).

Liquid/liquid extraction/purification of impure solutions of rare earth values

Abstract: Aqueous nitric solutions of salts of at least one rare earth, and containing contaminating amounts of at least one alkaline earth cation, e.g., calcium, barium and/or radium, are conveniently purified by liquid/liquid extracting same with an organic phase which comprises a polyether extractant for said at least one alkaline earth cation, e.g., a crown ether, and whereby said at least one alkaline earth cation is selectively transferred into said organic phase.

Novel surface-active compositions containing polydicarboxylic acid polymer and surfactant

Abstract: Novel surface-active, storage-stable compositons well adopted for the formulation of a variety of active agents, e.g., biocides, and the conversion thereof into stable, hmogenous liquid suspensions, are comprised of at least one first polyolefinic copolymeric surface-active agent (a) and at least one second mixed sulfate and/or phosphate ester surface-active agent (b).

Organopolysilazane composition containing free radical generators and capable of being crosslinked by an energy input

Abstract: An organopolysilazane composition that can be crosslinked by an energy input. The organopolysilazane composition comprises an organopolysilazane and a free radical generator in an amount effective to crosslink the organopolysilazane. The energy input capable of generating the radical may be provided in the form of heat, ultraviolet radiation, an electron beam, and the like. The crosslinked organopolysilazane compositions exhibit good thermal behavior and, in particular, can be used, after pyrolysis, as precursors of ceramic products.

Masterbatches for delustring polyamides

Abstract: The present invention relates to masterbatches for delustring processable polyamides. They contain 50 to 90% of a copolyamide used as a binder and consisting of 30 to 100% of hexamethylene adipamide units and 0-70% of caproamide units and 10 to 50% by weight of anatase titanium dioxide coated with 0.01 to 1.5% of silica and 1 to 3% of alumina and treated with a polydimethylsiloxane oil present in a proportion of 0.2 to 10% by weight of TiO 2 . They are obtained by adding TiO 2 powder into the autoclave immediately after the pressure release stage, when the reaction mass is still at a high temperature and before vacuum is applied. The masterbatches according to the invention may be introduced directly into the liquid stream of the polymer to be spun.

Preparation of ceric alkoxides in glycol ethers

Abstract: The preparation of cerie isopropoxide from ceric ammonium nitrate in dimethoxyethane (DME) and isopropanol (IPA) is described in detail. Quantitative yield is obtained when sodium isopropoxide is used as a base. When ammonia, instead of sodium isopropoxide, is used the reaction has difficulty going to completion because of an apparent equilibrium. We show that NH4NO3 reacts with pure cerium isopropoxide in DME liberating NH3 and IPA.

Process for a two-step preparation of reticulated organopolysilazanes which possess enhanced thermal properties, in particular for use as a precursor for ceramics

Abstract: In a first stage, the aminolysis of a dichlorosilane and/or of a dichlorodisilane is carried out and the amine chloride formed is removed and, in a second stage, the aminolysate obtained during the first stage is reacted with at least one organosilicon compound chosen from an organochlorosilane, an organochlorodisilane, an organochloropolysilazane and an organochloropolydisilylsilazane containing at least three chlorine atoms per molecule, in the presence of a tertiary amine. A cationic polymerisation may be advantageously optionally carried out on the aminolysate obtained in the first stage. The polysilazanes thus treated exhibit a high heat resistance and can be employed especially as precursors of ceramic products, with a high yield of mineral product.

Stabilized zirconia a process for its preparation and its application in ceramic compositions

Abstract: A fine powder of stabilized zirconia a process for its preparation and application of the powder in ceramic compositions to obtain good mechanical, thermomechanical and electrical properties. A zirconia hydrate sol having a pH between 0.5 and 5 and containing elementary acicular crystals having dimensions of from about 10 to 500 Å which are agglomerated into submicron aggregates of from abuot 100 to 5000 Å in diameter is mixed with a solution of a stabilizing agent, preferably yttrium; the suspension is dried; the dried suspension is calcined at a temperature of from about 700° C. to 1,300° C. for preferably from about 30 minutes to 24 hours; and if needed, the powder obtained is milled.

Ceric oxide particulates having a stable specific surface and a process for their preparation

Abstract: A ceric oxide composition, the specific surface of which remains essentially stable at elevated temperatures and which is thus well adopted for purposes of catalysis, is comprised of a plurality of solid, porous, finely divided ceric oxide particulates, said ceric oxide particulates advantageously having an effective amount of at least one oxide of another metallic element A intimately dispersed therein as to essentially prevent the coalescence of the micropores thereof.

Elastomeric silicone depilatory

Abstract: Unwanted hair is removed from selected skin area by applying a coating of a curable organopolysiloxane composition thereon, permitting the organopolysiloxane composition to crosslink into a silicone elastomer, e.g., in the form of a solid layer or foam, and embed unwanted hair therein, and then stripping the silicone elastomer and embedded hair from said skin area, whereby said skin area is essentially depilated.