Abstract: A method for electrochemically purifying solutions with a pH higher than 14 to reduce metal impurities to the level of traces. The method comprises processing the solutions in an electrolytic cell in which the cathode has a fibrous web produced from a mixture of fibres including at least one fraction consisting of electrically conductive fibres and a binder selected from fluoropolymers, said fibrous web being deposited on an electrically conductive porous support. Said cathode may also be combined with a diaphragm or a membrane. A cathode having a fibrous web produced from a mixture of carbon fibres, cellulose compounds, and a cationic polymer such as cationic starch is also disclosed.

Abstract: A composition containing, as active ingredient, one or more water soluble plant protection active materials and further containing an effective amount of one or more polyalkoxylated amidoamines of average formula (1) or (2), wherein all R.sup.1, which are the same or different, are a straight or branched C.sub.2 -C.sub.22 alkyl or alkenyl hydrocarbon group, cycloalkyl or alkylaryl, all R.sup.2, which are the same or different, are hydrogen or a C.sub.1 -C.sub.4 alkyl radical, and p, q, r, s and t, which are the same or different, are integers that can be zero, such that p+q is 1-20 and r+s+t is 1-20. Applications of said composition as a herbicide, a fungicide or a fertilizer are also described.

Abstract: The present invention relates to silicas, in particular precipitated silicas, which can be used in particular as abrasive agents in toothpaste compositions. The silicas according to the invention have, first of all, low specific surfaces. Their BET specific surface is between 20 and 75 m.sup.2 /g, preferably between 35 and 64 m.sup.2 /g. The invention also relates to a process for their preparation and to the toothpaste compositions containing them.

Abstract: The invention relates to the use as a luminophor in plasma systems of a compound based on an yttrium, lanthanum, gadolinium or lutecium phosphate doped with at least one rare earth chosen from the group comprising terbium, praseodymium, europium and cerium.

Abstract: A stripping and/or cleaning composition is disclosed, which contains, by volume: (a) 1 to 90% of at least one C.sub.1 -C.sub.4 dialkyl ester of at least one C.sub.4 -C.sub.6 aliphatic diacid; and (b) 99 to 1% of at least one ether selected from the group consisting of ethers with a flash point above 5.degree. C., at least one methoxy group per molecule and a molecular weight of less than 200.

Abstract: The present invention relates to a process for the purification of a medium containing organic waste. The process according to the present invention is characterized in that the starting medium (or effluent) containing the organic waste is subjected to the following stages: (i) treatment with at least one oxidizing agent; (ii) treatment with at least one flocculating agent; (iii) treatment with at least one polyelectrolyte, and in that the effluent obtained on conclusion of all of these stages is subjected to a filtration stage (iv), whereby a filtration cake and a filtrate are obtained. The process according to the present invention is more particularly useful for the treatment of pig manure.

Abstract: The instant invention relates to a process for the preparation of fluoroanilines of formula (I) wherein a fluorinated nitrated benzene compound of formula (II) is subjected to a catalytic hydrogenation in a liquid medium containing a catalyst, under hydrogen pressure, carrying out a catalytic reduction reaction and, optionally, a hydrogenolysis reaction, wherein the compound of formula (II) is introduced gradually into the said medium so that the content of compound of formula (II) in the liquid remains less than or equal to 1000 ppm by mass, in order selectively to form the compound of formula (I).

Abstract: The subject of the present invention is a composition comprising:at least one masked or unmasked polyisocyanate in the form of an aqueous emulsion whose mean size is between 0.1 and 10 micrometres and preferably smaller than 2 and larger than 0.2 micrometres,at least one polyhydroxylated polymer, advantageously a polyol, in the form of a second aqueous dispersion whose mean size is between 10 and 200 nanometres.This composition is defined in that the quantity of polyol in the mixture is chosen so as to meet one of the following two constraints:the polyol content, expressed in mass percent, is at least equal to 35-0.75R, advantageously at least equal to 40-0.75R, preferably to 45-0.75R;the polyol content, expressed in mass percent, does not exceed 45-2R, advantageously does not exceed 40-2R, preferably 35-2Rwith R equal to the ratio of the mean size (d.sub.50) of the emulsion to that of the polyol dispersion.Application to organic synthesis.

Abstract: The present invention concerns a process for the acylation of an aromatic ether.Preferably, the invention relates to a process for the acylation of an unsubstituted aromatic ether, in particular anisole.The acylation process of the invention consists of reacting the ether with an acylation agent in the presence of a zeolitic catalyst, and is characterized in that the acylation reaction is carried out in the presence of an effective quantity of a catalyst comprising a beta zeolite with an atomic ratio denoted "global Si/Me.sup.1 " between the number of atoms of the element silicon and the number of atoms of every trivalent element Me.sup.1 contained in the zeolite of no less than 15, preferably in the range 15 to 55, and more preferably in the range 18 to 35.

Abstract: The present invention concerns a process for the hydroxyalkylation of a carbocyclic aromatic ether.The invention preferably relates to the preparation of 3-methoxy-4-hydroxybenzyl alcohol by the hydroxymethylation of guaiacol.It also concerns the oxidation of the hydroxyalkylated ethers obtained, in particular the oxidation of 3-methoxy-4-hydroxybenzyl alcohol to 3-methoxy-4-hydroxybenzaldehyde, commonly known as "vanillin".The process for the hydroxyalkylation of a carbocyclic aromatic ether of the invention consists of reacting the aromatic ether with a carbonyl compound in the presence of a catalyst and is characterized in that the hydroxyalkylation reaction is carried out in the presence of an effective quantity of a zeolite.

Abstract: The invention relates to a new process for the preparation of precipitated silica which has an excellent dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 140 and 200 m.sup.2 /g, a BET specific surface of between 140 and 200 m.sup.2 /g, a DOP oil uptake lower than 300 ml/100 g, a median diameter, after disintegration with ultrasound, smaller than 3 .mu.m, an ultrasonic disintegration factor higher than 10 ml and an aluminium content of at least 0.35% by weight. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers.

Abstract: The present invention concerns a process for the preparation of 3-carboxy-4-hydroxybenzaldehydes and derivatives thereof from phenolic compounds carrying formyl and/or hydroxymethyl groups in the 2 and 4 positions.The invention also concerns the preparation of 4-hydroxybenzaldehydes from 3-carboxy-4-hydroxybenzaldehydes.More particularly, the invention concerns the preparation of 3-methoxy-4-hydroxybenzaldehyde and 3-ethoxy-4-hydroxybenzaldehyde, respectively known as "vanillin" and "ethylvanillin".The process for the preparation of 3-carboxy-4-hydroxybenzaldehyde is characterized in that the group in the 2 position in a phenolic compound carrying formyl and/or hydroxymethyl groups in the 2 and 4 positions is selectively oxidized to a carboxy group, and optionally a hydroxymethyl group in the 4 position is selectively oxidized to a formyl group.A successive decarboxylation step for a 3-carboxy-4-hydroxybenzaldehyde produces a 4-hydroxybenzaldehyde.

Abstract: A method for obtaining substantially pure toluylene 2,6-diisocyanate from a mixture of the 2,4 and 2,6 isomers of toluylene diisocyanate, wherein at least one crystallizing-melting cycle is performed on the mixture of said isomers to separate out the toluylene 2,6 diisocyanate isomer. In an alternative embodiment, the mixture is contacted, prior to the crystallizing-melting cycle, with a compound or catalyst capable of converting part of the toluene 2,4-diisocyanate isomer therein, and the reacted 2,4 isomer is separated. Said method is advantageous in that usable by-products are produced.

Abstract: The invention relates to a process of treatment for the recovery of the precious metals, such as platinum, rhodium and palladium, contained in various compositions including a layer of oxide(s) which is deposited on a metal support, in particular worn or spent motor vehicle postcombustion catalysts, in which the layer of oxide(s) containing the precious metals is separated from the metal support by an electrochemical route, the composition to be treated forming one of the electrodes employed or being in direct contact with one of the electrodes employed.

Abstract: The present invention relates to a novel presentation of a product exhibiting the phenomenon of supercooling. More precisely, the subject of the invention is cristallized pearls of a product exhibiting strong supercooling. The invention also relates to the preparation of the said pearls. The characteristic feature of the process of the invention is to melt, if necessary, the product to be shaped; to break up the molten mass into droplets; to cool the droplets to a temperature below the glass transition temperature of the product, so that these droplets harden by vitrification; to maintain the pearls thus vitrified at a temperature below the glass transition temperature and to place them in contact with crystallization seeds; to crystallize the pearls by raising the temperature above the glass transition temperature and then to recover the crystallized pearls.