Abstract: Purification of haloaldehydes in a process that consists essentially of a first stage of purification in which the haloaldehydes are brought into contact with an absorbent solid, basic in nature, in the presence of water or free alcohols, and of a second stage of purification in which the halo-aldehydes thus treated are brought into contact with a solid absorbent carrying sulphonic, phosphonic or carboxylic acid groups in the form of salts of alkali or alkaline earth metals.

Abstract: Titanium dioxide is post-treated by flowing it in a tubular zone as a suspension in a stream of carrier gas, injecting a gaseous stream of halides of Si, Ti and Al in said stream and then steam in the resulting mixture, once the latter is homogenized.

Abstract: Soil modifiers comprising from 80 to 95% by weight of a mixture of ferric oxide and ferric sulphate in an oxide/sulphate weight ratio of from 0.2:1 to 2:1 are prepared by calcining at 500.degree.-600.degree. C in the presence of an oxidizing gas a material consisting essentially of ferrous sulphate with an average number of molecules of crystallization of from 1 to 5 obtained by partial dehydration of the waste materials, consisting essentially of ferrous sulphate heptahydrate, obtained in the manufacture of titanium dioxide from ilmenites or ilmenite slags by the sulphate process. These modifiers are particularly suitable for clay soils.

Abstract: The constituents of an exhausted toluene-dimethylformamide solvent mixture used for removing polyvinyl chloride deposits from polymerization reactors, are separated by adding water to said mixture and distilling off toluene, thereby to obtain a distillation residue having a water content of at least 2 wt.% and a toluene content not exceeding 10 wt.%, precipitating the polymer by cooling the distillation residue, adding a further amount of water, distilling off any toluene present, recovering the precipitate and distilling the residual aqueous solution to recover the dimethylformamide.

Abstract: Process for the separation of trioxane from aqueous solutions containing it together with formaldehyde, which comprises subjecting the said solutions to evaporation at temperatures of 100.degree. C or lower, at pressures lower than atmospheric, and with residence times of less than 1 minute under the evaporation conditions, with vaporization of a quantity of from about 5 to about 15% by weight of the solution introduced, and recovering the trioxane from the products evaporated in this way.

Abstract: Crude ethylene oxide present in the dilute aqueous solution resulting from the extraction with an aqueous solvent of ethylene oxide from the gaseous stream obtained by catalytic oxidation of ethylene is purified by desorption, liquefaction, distillation in a fractionating column and final desorption treatment to remove absorbed non-condensable gases. The fractionating column is heated by condensation of the water vapor evolved during desorption and a liquid stream of ethylene oxide rich in acetaldehyde is discharged from the bottom, treated to convert a fraction of said acetaldehyde into high-boiling products, distilled to remove the latter as bottoms and returned to the fractionating column.

Abstract: Nitric acid having a concentration of at least 98% by weight is obtained from a gaseous stream resulting from catalytic oxidation of ammonia and containing nitrogen oxide and steam, by flowing said stream in an oxidation and condensation column in countercurrent with a stream of nitric acid at 40-60 wt.%, recovering nitrogen peroxide at the top of the column, liquefying said peroxide, bringing it into contact with aqueous nitric acid, oxygen and air in a chemical absorption stage, and distilling the resulting superazeotropic nitric acid. A part of the nitric acid discharged from the oxidation column is directly recycled and the remainder is recycled after distillation to give azeotropic acid and remove water, a part of the latter being used for the chemical absorption.

Abstract: Saline water is desalted by flowing it in two evaporation stages in series in the form of a film falling on the inside of heat-exchange tubes. The pressure and temperature in the second evaporation stage are lower than in the first stage. The steam evolved in the second stage is compressed and delivered to the first stage where it condenses on the tubes, whereas the steam evolved in the first stage is fed in the second stage where it condenses on the tubes. The condensation heat of the steam is used for vaporizing said saline water from said film. This technique allows a production of 15-50 cu.m/hr of soft water, instead of a production of 15-20 cu.m/hr usually obtained by conventional thermocompression techniques.

Abstract: Process for the preparation of catalysts suitable for the production of linear olefins by dimerization or co-dimerization of linear olefins having small numbers of carbon atoms, characterized by depositing one or more metals chosen from among those belonging to group VIII of the periodic system of elements on a natural or synthetic crystalline zeolite by ion exchange to a quantity of deposited metal of from 0.1 to 50% by weight with respect to the zeolite itself, by bringing the resulting product into contact with an organic or inorganic base in the liquid or gaseous form at a temperature in the range from -35 to 250.degree. C for a time of at least 30 minutes, and by eliminating the excess of the base and heat-treating at temperatures in the range from 50 to 450.degree.

Abstract: Vinylidene chloride polymers and copolymers are prepared by contacting vinylidene chloride monomer alone or in mixture with other ethylenically unsaturated monomers with a catalytic system consisting of an organic per-compound, an organic compound of zirconium or cobalt and an acid compound according to the definition of Bronsted and Lowry in an organic solvent medium.High yields and polymerization speeds are achieved at low polymerization temperatures (10.degree.-35.degree. C).

Abstract: Diepoxides of the general formula: ##STR1## wherein n has an average value not exceeding 0.03 and R is the bisphenyl radical of bisphenol-A are recovered from an epoxy resin of the same general formula with n varying from 0.07 to 0.30, by removing the low-boiling substance from the epoxy resin at 0.1-1 mm Hg and 165.degree.-200.degree. C and distilling off said diepoxide from the thus treated epoxy resin at 0.1-0.005 mm Hg and a temperature not exceeding 240.degree. C. The low viscosity, narrow molecular weight distribution and excellent purity of these diepoxides allow their use in critical application fields.

Abstract: Methyl acrylate alone or in mixture with acrylic acid is prepared by passing a gaseous stream containing methanol, acrolein and oxygen at a velocity of 5 to 50 cm/sec through a fluidized catalytic bed formed of spherical particles 15 to 100 .mu. in size, said particles comprising from 10 to 80 wt.% silica support, the remainder consisting of an active catalytic component defined by one of the general formulae:Mo.sub.a V.sub.b Me.sub.c O.sub.xMo.sub.a W.sub.d Me.sub.c O.sub.yMo.sub.a V.sub.b W.sub.d Me.sub.c O.sub.zwherein Me is Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Au, Hg, Na, Ba, Ca, Ce, Bi, Th, U, Pb, Sb, Sn, P or B; and wherein a is a number from 6 to 12, b from 1 to 6, c from 0 to 5, d from 1 to 6, x from 20.5 to 58.5, y from 21 to 61.5 and z from 23.5 to 76.5.

Abstract: A catalyst active and selective in the oxidation of methanol to formaldehyde is prepared by mixing an aqueous molybdate solution with an aqueous solution of a ferric salt, while maintaining a Mo/Fe atomic ratio of from 1.6:1 to 2.2:1 in the mixture, heating the resulting suspension at 70.degree.-100.degree. C for at least 30 minutes, washing the resulting precipitate with water, drying said precipitate to reduce its water content to 2-8% by weight, reducing the dried precipitate to granules and drying the latter to completely remove water, impregnating the dried granules with an aqueous solution of a decomposable bismuth salt and drying and calcining the impregnated granules. The catalyst consists of granules of crystalline iron molybdate and molybdenum trioxide having on their surface an interaction product thereof with bismuth oxide, said molybdenum trioxide and said bismuth being present in an amount of 5-35 wt.% and 0.5-10 wt.%, respectively, with respect to the crystalline iron molybdate.

Abstract: Linear mono-olefines are prepared by contacting linear paraffins having from 6 to 16 carbon atoms per molecule with a porous dehydrogenation catalyst comprising beryllium oxide as a support and from 0.01 to 10% by weight of noble metal as active component.

Abstract: A solution of active nuclei for the hydrolysis of titanium sulphate and for the rutilisation of titanium dioxide in the manufacture of titanium dioxide in tutile form in the method via sulphate is prepared by transforming titanium tetrachloride into a compound of the formula Ti(OH).sub.x Cl.sub.y, wherein x ranges from 1 to 3, y from 3 to 1 and x + y is equal to 4 by contact with steam in the vapor phase, and contacting the reaction products with an aqueous solution of sodium hydroxide to form an aqueous suspension of titanium hydroxide having a TiO.sub.2 content of from 10 to 30 grams/liter and a pH value of from 3 to 4.

Abstract: Nitric acid having a concentration of at least 98 wt.% is produced from nitrogen peroxide by absorbing the latter in superazeotropic nitric acid, distilling the resulting solution so as to recover nitric acid at a concentration of at least 98 wt.% and nitrogen peroxide, liquefying the latter and reacting it in a first stage with aqueous nitric acid (70-80% wt.%) and air and delivering the resulting superazeotropic nitric acid, together with the solution, to the distillation column. Nitrogen peroxide and oxygen unreacted in the first stage are contacted with nitric acid at 68-75 wt.% in a second stage, thus to produce said aqueous nitric acid fed to the second stage. The said nitric acid at 68-75 wt.% and the superazeotropic acid used for the absorption are extracted from the bottom part of the distillation column.

Abstract: Nitric acid having a concentration of at least 98 wt.% is prepared by recovering in liquid state nitrogen peroxide from a gaseous flow containing the same, by absorption in nitric acid, heating of the resulting solution and liquefaction of the gaseous peroxide evolved, followed by a first chemical absorption of a fraction of the liquid peroxide with nitric acid at 70-80% and air and distillation of the resulting concentrated nitric acid. The gaseous products discharged from said first absorption and comprising unreacted peroxide and air are contacted with nitric acid and water in a second chemical absorption stage, thereby to produce the nitric acid used in the first absorption. The remaining fraction of liquid peroxide is delivered to the distillation column, discharged at the top thereof and recycled to the liquefaction stage, while nitric acid is extracted at the bottom of the distillation column and recycled to the second absorption stage.

Abstract: Aluminum trichloride is separated and recovered from its complexes with hydrocarbons and hydrogen chloride by contacting the complexes with metallic aluminum at 20.degree.-100.degree. C and recovering the resulting precipitate of aluminum trichloride.

Abstract: Liquid epoxy resins are produced by contacting a dihydroxy phenol with an excess of epihalohydrin and an aqueous solution of an alkali metal hydroxide in a molar ratio of hydroxide to phenol not exceeding 2:1, recovering from the reaction products an epoxy resin having a content of hydrolyzable chlorine of from 1 to 6% by weight, contacting a solution of the resin in a hydrocarbon with an aqueous solution of an alkali metal hydroxide while maintaining an atomic ratio of alkali metal to hydrolyzable chlorine contained in the resin of from 1:1 to 1.17:1 and recovering from the reaction products a liquid epoxy resin having a content of hydrolyzable chlorine less than 0.02% by weight.These epoxy resins of high purity are particularly useful as varnishes or coatings.

Abstract: Titanium sulphate solutions obtained in the sulphate process from titaniferous materials are hydrolized by contacting at 88.degree.-98.degree. C water with a first titanium sulphate solution having a TiO.sub.2 titer of 230-260 g/l and an acid factor of 1.75-1.85, adding at 88.degree.-98.degree. C to the mixture a second titanium sulphate solution having a TiO.sub.2 titer of 230-260 g/l and an acid factor of 2.1-2.4 and heating the resulting mixture at boiling point. A volumetric ratio of from 3:100 to 12:100 is maintained between the first and the second solution.