Rhone-poulenc Chimie

Rhone-poulenc Industries

Rhodia Chimie

Rhone-poulenc Specialites Chimiques

Other

Adrien Dromard

Michel Costantini

Michel Jouffret

Yvonick Chevallier

Claude Millet

Claude Richard

Dominique Petit

Gérard Mignani

Pierre-Yves Lahary

Rémi Valero

Lucile Gambut

Roland Nantermet

Ramanadin

Fr&eacute;d&eacute;ric Amiche

Jean-Francois Viot

Céline Marcandelli

Frédéric Dallemer

Remi Valero

Fr&egrave;d&egrave;ric Amiche

The invention relates to a highly-structured precipitated silica having a low water uptake and high dispersibility in different pasty or solid matrices or media, elastomers or silicon, and to the preparation method thereof. The invention also relates to the use of said silica, for example, as a reinforcing filler in matrices based on elastomers (clear or semi-clear for shoe soles), in silicon matrices (in particular, for the coating of electric cables), as a filler and/or support and/or vehicle in different compositions (food compositions, cosmetic compositions, pharmaceutical compositions, compositions for the production of paints or paper, compositions for the production of porous membrane separators for batteries) or as a thickening agent in toothpastes.

Highly-structured silica having a low water uptake, preparation method thereof and uses of same

The invention concerns the use, as thickening or texturing agent in toothpaste compositions, of a highly dispersible precipitated silica having a pH of 3.5 to 9, a DOP oil absorption higher than 200 ml/g, a CTAB specific surface area from 70 to 250 m2, a median diameter of at least 20 &#x3bc;m determined by ultrasound-free laser diffraction, a residual anion rate, expressed in sodium sulphate, less than 5 wt. %.

Use of a high structure and dispersible precipitated silica as a thickening or texturing agent in toothpaste compositions

The invention concerns polyorganosiloxanes (POS) grafted with peroxide functions and functions stabilizing the latter. Said stabilized peroxidised POS are designed to form a novel oxidizing system useful as bleaching agents, for example or dental or detergent compositions. The invention aims at and succeeds in providing peroxygenated bleaching agents more stable and more efficient than those known in prior art. The inventive stabilized and peroxidised POS correspond for example to the formula (a). The invention also concerns a method for making said peroxidised POS, the precursors thereof and their uses as bleaching agents in dental compositions (toothpaste or detergent compositions).

Peroxidised polyorganosiloxanes (POS), one of the methods for preparing them and their uses as bleaching agent in dental compositions

Process for preparation of abrasive precipitated silica

The invention discloses an abrasive precipitation silica useable in toothpaste compositions, said silica having a BET specific surface ranging from 15 to 300 m,/g, a DOP oil absorption ranging from 40 to 160 ml/g, a median particle diameter of at least 10 &mgr;m, generally ranging from 12 to 30 &mgr;m, a particle cohesion factor of at least 85% about for a median particle diameter ranging from 12 to 20 &mgr;m. Method for preparing silica by reacting an alkaline metal silicate with an acidifying agent, to form a silica slurry, separating and optionally drying the recuperated silica suspension, the operation for forming the slurry being effected according to the following steps: a first step consisting in using one initial heel solution constituted of water, an electrolyte salt of the alkaline or alkaline-earth metal group and optionally of one acidobasic agent; a second step consisting in introducing the silicate and the acidifying agent, the reaction medium pH remaining constant from 4 to 7 and particularly from 5.8 to 6.7; and a third optional step, consisting in acidifying the reaction medium until a silica slurry with a pH of less than 6 and particularly of 4 is obtained. The silica is useful in toothpaste compositions. Toothpaste compositions containing the said silica are also disclosed.

Silica capable of being used in toothpaste compositions

Silica compatible with flavors, exhibiting, at an RP/DA abrasivity lower than or equal to 10, a compatibility with flavors which is higher than 10% and, at an RP/DA abrasivity higher than 10, a compatibility with flavors of at least 30%. Process for the preparation of flavor-compatible silica by treating the surface of a silica originating from the reaction of an alkali metal silicate with an inorganic or organic acidic agent, the silica being in dry form or in an aqueous suspension, with the aid of an organic compound capable of developing hydrogen bonds or ionic bonds with, respectively, the Si--OH silanol groups or the SiO.sup.- anionic groups at the surface of the said silica to be treated, the said treated silica being subsequently, if necessary, isolated and/or washed and/or dried. Use in dentifrice compositions and dentifrice compositions including the said silica.

Silica compatible with flavors, process for its preparation and

Abrasive silicas for toothpaste compositions

Phenolic compounds, e.g., phenol, are hydroxylated, preponderantly into the para-isomer, e.g., hydroquinone, by reaction with hydrogen peroxide in the presence of an effective amount of a strong acid and a catalytically effective amount of a keto compound having the formula (II): ##STR1## in which R.sub.1 and R.sub.2, which may be identical or different, are each a hydrogen atom or an electron-donating group; n.sub.1 and n.sub.2, which may be identical or different, are numbers equal to 0, 1, 2 or 3, with the proviso that the two carbon atoms located at the .alpha.-position with respect to the two carbon atoms bearing the --CO group may be bonded together via a valence bond or via a --CH.sub.2 -- group, thereby forming a keto-containing ring member which may either be saturated or unsaturated.

Hydroxylation of phenolic compounds

Stable aqueous suspensions of precipitated silica, well adopted as coatings for the papermaking industry, include an aqueous suspension of a slaked precipitated silica filter cake and an effective amount of a stabilizer therefor, which stabilizer contains (a) aluminum or an aluminum compound, and (b) an anionic dispersing agent.

Aqueous suspensions of precipitated silica with anionic dispersant and

Stable, non-gelling and pumpable aqueous suspensions of precipitated silica particulates, well adapted for the coating of paper and cardboard substrates, include an effective stabilizing amount of at least one biogum heteropolysaccharide and at least one quaternary ammonium, sulfonium or phosphonium compound (cationic surfactant).

Stable, pumpable aqueous suspensions of precipitated silica particulates

Polysiloxanes of relatively low molecular weight are catalytically polymerized/rearranged into high molecular weight polysiloxanes in the presence of a cationic catalyst comprising a porous, inorganic mineral particulate support having an average pore diameter in excess of 20 .ANG. and a pore volume ranging from 0.2 to 2 ml/g, said porous support being coated with less than 15 mg/m.sup.2 of a film of polymeric material comprising pendant sulfonic or phosphonic acid functions, and said polymeric material being characterized by an ion exchange capacity of less than 2 milliequivalents per gram.

Catalytic preparation of high molecular weight polysiloxanes

Process for preparing anion exchange resins comprising polymerizing a vinyl aromatic compound having at least one alkyl group containing about 1 to 3 carbon atoms, alone or mixed with a copolymerizable monomer, optionally in the presence of a mineral support, followed by brominating the alkyl groups of the resulting polymer by means of an N-bromoamide or an N-bromoimide, and then aminating the brominated product obtained. The resulting anion exchange resins are useful in the chemical, pharamaceutical, food, and metallurgical industries.

Preparation of anion exchange resins by bromination of vinyl aromatic

Aromatic compounds of the general formula ##STR1## in which R and R.sub.o represents a hydrogen atom or an alkyl radical of 1 to 4 carbon atoms are hydroxylated by reaction with hydrogen peroxide in the presence of a catalytic amount of a strong acid and the reaction is carried out in the presence of an activator which is a juxtanuclear aromatic aldehyde or derivative thereof selected from an acetal or a benzhydrol.

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Lyons, France

Adrien Dromard