Abstract: Process for producing mixtures of methanol and higher alcohols comprising feeding, into the reaction zone equipped with a catalytic system, H.sub.2, CO and possibly inert products with a molar ratio H.sub.2 /CO of between 0.2 and 10, at a temperature of between 200.degree. and 460.degree. C., at a pressure of between 2,000 and 30,000 KPa, and at a space velocity of between 1,000 and 40,000 GHSV, wherein the catalytic system corresponds to the following empirical formula:Zn.sub.x Cr.sub.y O.sub.t +z%M.sub.2 Owherein the x/y ratio is greater than 0.5 and less than 1, t is what is necessary for satisfying the valence with which the various elements appear in the catalyst,M is an alkaline metal selected from potassium and cesium,z, representing the percentage of alkaline oxide of the final catalyst, when the metal is potassium, is between 0.01 and 8 and, when the metal is cesium, between 0.01 and 20.6.

Abstract: Improved yield process for urea synthesis by starting from ammonia and carbon dioxide, comprising a reaction zone under high pressure and temperature conditions, a section wherein a portion of unreacted ammonia and carbon dioxide are stripped and recycled to the reactor, which section operates under substantially the same reactor pressure, and a subsequent section, operating under medium and/or low pressure conditions, for urea purification and simultaneous recovery of residual carbon dioxide and a portion of residual ammonia contained in the effluent stream from the stripping section, as an aqueous solution of ammonium carbamate, in which said aqueous ammonium carbamate solution is either totally or partially fed to said stripping section. Said process makes it possible a conversion of carbon dioxide into urea to be obtained in the reactor which is higher than 70%.

Abstract: A process for the synthesis of urea starting from ammonia and carbon dioxide, comprising a reaction step carried out in at least two distinct operating zones basically at the same pressure, but having a different operating temperature, the difference being preferably between 5.degree. and 60.degree. C., and subsequent separation steps of the non-converted reagents, wherein a gaseous stream is transferred from the first zone, at a higher temperature, to the second zone, at a lower temperature, and a liquid stream, containing urea and/or ammonium carbamate, is transferred from the second zone to the first, so that said gaseous stream is preferably at least 5% by weight with respect to the stream effluent from the first zone to the subsequent separation steps. This process allows a ratio urea/(urea+carbamate), in the stream leaving said reaction step, of more than 70%, to be obtained.

Abstract: Process for vacuum-concentrating urea solutions in which the final step of evaporation of the urea solution under vacuum is carried out within the injection of overheated water vapor in the overhead portion of the concentrator, in order to counteract the formation and deposition of high-melting, fouling compounds derived from urea.

Abstract: A process is described for the joint production of ethers and hydrocarbons with a high octane number starting from C.sub.4 hydrocarbon cuts containing isobutene, by oligomerization with acid catalysts, in the presence of primary alcohols selected from methanol or ethanol in such a quantity as to have a molar ratio primary alcohols/isobutene in the feeding of between 0.2 and 0.7, preferably operating at a reaction temperature of between 30.degree. and 100.degree. C. and at feeding space velocities of less than 20 h.sup.-1.

Abstract: Integrated process for the production of ter-amyl alkyl ethers which comprises the feeding of a C.sub.5 hydrocarbon stream to an etherification reactor and the recycling of the remaining stream to the same reactor, after treatment in an isomerization section to convert linear pentenes into reactive isoamylenes. An absorption section on molecular sieves is inserted between the etherification reactor and the isomerization section to eliminate inert hydrocarbons, basically i-pentane and n-pentane.

Abstract: A fluidized bed reactor operating under countercurrent gas-solid flow conditions wherein the reactor is supplied with horizontal baffles having separate passages through which the gas and the solid flow, such that the ascending gas leaves the baffle in a point higher than the point in which the descending solid leaves the same baffle, and the use of the reactor to perform reactions under countercurrent flow conditions while maintaining gas and solids flows of at least 70% of flooding conditions.

Abstract: A process for dehydrogenating light paraffins, in particular C.sub.2 -C.sub.5, to obtain the corresponding light olefins, comprising reacting said paraffins with a catalytic system containing platinum, tin and an alumina support and possibly an element of the lanthanide group in a fluidized bed reactor, where the heat required for the reaction is provided by said catalytic system as sensible heat, operating at a temperature of between 500.degree. and 700.degree. C. and at a pressure of between 1 and 2 kg/cm.sup.2, and regenerating said catalytic system by burning the coke which has deposited on the surface of the catalytic system, said regeneration being conducted in air and/or oxygen, if necessary by increasing the temperature of the catalytic system to a suitable level, followed by reduction of said catalytic system with a reducing agent.

Abstract: A catalyst system for the liquid-phase production of methanol from synthesis gas is described, consisting of:one or more copper compounds;one or more alkoxides of the lanthanum group of formula (R.sub.1 O).sub.x Ln and/or one or more inorganic oxides of the lanthanum and/or aluminium group;one or more alkaline and/or alkaline-earth alkoxides of formula (R.sub.a O).sub.x M,if at least one alkoxide of the lanthanum group is present, then one or more alkoxides of the titanium group of formula (R.sub.t O).sub.x T is present,where R.sub.1, R.sub.a and R.sub.t, which can be the same or different, are C.sub.1 -C.sub.10 alkyl groups,M is the alkaline or alkaline-earth metal,Ln is an element or the lanthanum group,T is an element of the titanium group,x is equal to the valency of the metal or element.

Abstract: Process for the skeleton isomerization of linear olefins, preferably n-butenes or n-pentenes, which consists in putting said olefins in contact with a catalyst comprising alumina on whose surface boron oxide is deposited in a quantity which is lower than 2.1.times.10.sup.-4 g/m.sup.2 of the surface of the alumina.

Abstract: A catalytically active gel is described consisting of a silica matrix with uniform porosity, monomodal pore distribution and high surface area, within which one or metal oxides possessing catalytic activity are dispersed. A process for preparing this catalytic gel is also described.

Abstract: An integrated process for the simultaneous production of alkyl tert-butyl ethers and 1-butene, comprising feeding a C.sub.4 hydrocarbon stream to an etherification unit and recycling the remaining stream to the same unit after possible separation of the 1-butene and treatment in an isomerization section to convert the remaining butenes into isobutene, a molecular sieve separation unit operating with the hydrocarbons in the vapour phase being incorporated into the cycle.

Abstract: This invention provides a seismic joint for an underwater floating tunnel having: (a) a joint portion (i) having a transverse section essentially the same as that of the tunnel, (ii) being rigidly fastened to land at one end (A) thereof, and (iii) being elastically constrained to the tunnel at its other end (B) via a plurality of operably affixed means which performs an elastic function and a damping function; (b) a collar welded onto the external surface of the tunnel facing end (B) of the portion, said collar being capable of sliding on and along the external surface of the joint portion; and (c) a means for providing a water-tight seal between the internal surface of the collar and the external surface of the joint portion.

Abstract: A process for neutralizing the ammonia present in the molten urea originating from the concentration section of a plant for its production, comprising adding to the molten urea a small quantity of an acid.

Abstract: Mono-alkadienyl alkyl ethers and di-alkadienyl alkyl ethers are prepared by telomerization of a conjugated diene, by causing said conjugated diene to react with an aliphatic alcohol or an aliphatic diol respectively, by operating in an aqueous/organic biphasic liquid system, in the presence of a catalytic system formed by:(a) a palladium salt or complex;(b) an alkyl-, alkylcycloalkyl-, or alkylarylphosphine ligand, bearing an acidic or neutral hydrophylic moiety, having the formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, x and y are as defined in the disclosure; and(c) an either inorganic or organic base.

Abstract: A process for the preparation of tertiary alkyl ethers, in particular methyl-tert.-butyl-ether (MTBE), from iso-olefins and aliphatic alcohols by means of a fractionation tower is disclosed, in which the main characteristic of the fractionation tower consists in that the reaction mixture is caused to flow through the catalytic trays in transversal direction relatively to the axis of the same fractionation tower.

Abstract: Disclosed is a low-viscosity cement composition, useful in the field of oil drilling, comprising cement, water and an additive obtained by salifying into the alkali-metal, alkali-earth metal, or ammonium salt, the sulphonated and oxidated products derived from the reaction between sulphur trioxide and cookery tar or sulphur trioxide and fuel oil from steam cracking; the cement composition is endowed with improved rheological characteristics such as a low-viscosity value without substantial changes in the pumping times, even at high temperatures and pressures.

Abstract: From a mixture containing methanol, ethanol, n-propanol, isobutanol water and other high-boiling and low-boiling compounds, the claimed process enables three separate streams to be obtained, one an anhydrous stream of methanol or methanol and ethanol (I), one containing most of the n-propanol present in the feed mixture (II), and one containing most of the isobutanol present in the feed mixture (III), by using three fractionating columns.

Abstract: A method, using a crane-equipped depot ship, for automatically repairing an underwater pipeline even if installed at great depth, comprising substantially the following steps: cutting off the damaged pipe piece by a single working module which, lowered onto the sea bed by a crane and clamped about said pipeline, removably supports the cutting apparatus; removing the concrete from the facing ends of the cut pipeline by said single working module which removably supports the removal apparatus, this being provided with an expansion-centering head; installing connectors by a sonar head alignment apparatus removably supported by said working module; and installing the replacement pipe piece by said working module using a reference and guide apparatus clamped about said ends of the pipeline. Specific apparatus for implementing the method are also described.

Abstract: A catalytically active gel product is described consisting of a silica matrix which is amorphous to x-rays with uniform porosity, monomodal pore distribution and high surface area, within which one or more metal oxides possessing catalytic activity are dispersed. A process for preparing this catalytic gel is also described.