Abstract:
An aromatic urethane (e.g., methyl naphthyl urethane) is prepared by reacting an aromatic hydroxy compound, such as alpha-naphthol, with an aliphatic urethane, such as dimethyl urethane, in the presence of a catalyst consisting of a Lewis acid.
Abstract:
In a method for the refrigerative fractionation of cracking gases in ethylene production plants, the improvement consisting in that ethane is used as the refrigeration fluid, it being thus possible to attain very low temperatures, down to minus 88.degree. C.: concurrently, the condensation with water is practicable whenever water is available in large masses at a temperature which is in the range from zero centigrade to +25.degree. C.; that is the case of sea waters in cold countries or fresh waters in cold climate. A considerable first-cost and running economy become thus available.
Abstract:
A compact structure is disclosed for supporting a pipeline suspended over a sea bottom vale. In a preferred embodiment, the structure has a triangular outline, the sloping side of the triangle being a guideway of a wedge slidable unidirectionally, that is only upwards, until contacting the pipe to be supported.Actuating mechanisms are provided for the movable members of the triangular structure. The entire structure is mounted on a base plate and can be towed by a subsea vehicle until reaching the correct position.
Abstract:
A method is disclosed for preparing carbonyl compounds from hydrocarbon streams coming from steam-cracking installations, the improvement consisting in that an alcohol is added to such a stream in a first reaction area and in the presence of an acidic ion-exchange resin the acidic centers of which have totally been exchanged with mercuric ions and with ions of alkali metals or alkaline earth metals, the resultant product being rectified to separate it from the hydrocarbon stream and then hydrolyzed in a second reaction area in the presence of an acidic ion-exchange resin and finally recovered by rectification.
Abstract:
The present invention provides a novel process for the separation of acetylenic compounds from saturated, olefinic and dienic hydrocarbons by etherifying the acetylenic compounds with an acyl compound in the presence of an acid ion - exchange resin containing mercuric ions.
Abstract:
A process is described whereby homopolymers and copolymers of isobutylene are prepared by effecting the polymerization at a temperature in the range of -100.degree. to 30.degree. C in the presence of a catalyst system including:(a) a compound selected from the group consisting of: AlCl.sub.3, AlBr.sub.3, AlEtCl.sub.2, TiCl.sub.4, SnCl.sub.4, SiCl.sub.4, VCl.sub.4, BF.sub.3, Al.sub.2 Et.sub.3 Cl.sub.3, SbCl.sub.5, SbF.sub.5, FeCl.sub.3, VOCl.sub.3, ZrCl.sub.4, AlI.sub.3, GaCl.sub.3 ; and(b) a compound adapted to react with the compounds of group (a) and selected from the group consisting of: SnR.sub.4, SnRX.sub.3, SrR.sub.4, TiX.sub.2 (OR).sub.2, Ti(OR).sub.4, PbR.sub.4, Ti(OR)X.sub.3, VO(OR).sub.3, Ti(OR).sub.3 X, (C.sub.5 H.sub.5).sub.2 Ti(C.sub.6 H.sub.5).sub.2, (C.sub.5 H.sub.5).sub.2 Ti(CH.sub.3).sub.2, Ti(Acac).sub.4, SnCl.sub.2 (acetate).sub.2 in which R is a hydrocarbon radical with from 1 to 10 carbon atoms and X is a halogen atom.The process is of particular value in the production of butyl rubber through the copolymerization of isobutylene and isoprene.
Abstract:
A macromolecular adenine derivative containing at least one unity having the general formula: ##STR1## wherein, n is 1, 2, 3 or 4; the radical: ##STR2## is derived from an adenine derivative wherein the amino group in position 6 in the adenine nucleus is functional; and the nitrogen atom, N
Abstract:
This invention relates to a method for constructing a thermoelectric module, as well as to the module so obtained. The method according to the invention comprises the steps of construction a reference shoulder on the semiconductor bar, assembling the semiconductor bars in series by using an insulating cement, cleaning the surfaces, gold plating, nickel plating, brasing copper electrodes, machining the regions between the elements which have to remain insulated, protecting the copper electrodes by nickel or chromium plating. The thermoelectric module so obtained consists of a matrix of semiconductor elements with all the mechanical and electrical connections incorporated, including the input and output terminals.
Abstract:
An enzymatic hydrolysis method is disclosed for the preparation of D-carbamyl aminoacids and the corresponding D-aminoacids.The method is based on the use of certain substituted hydantoins as the starting materials and these are hydrolized, in a temperature range from 10.degree. C to 70.degree. C, with hydropyrimidine hydrolase from calf livers. The pH range is from 8 to 9.The method in question is cheaper and more reliable than those of the prior art.
Abstract:
A process for the preparation of substituted indolenines of the formula: ##STR1## wherein R is hydrogen, alkyl, aryl or cycloalkyl, halogen, or a functional group selected from among cyano, hydroxyl, alkoxy, nitro or sulphonic groups, and wherein R.sub.1, R.sub.2 and R.sub.3 are the same, or different, and are selected from alkyl, aryl or cycloalkyl radicals, comprising reacting in the presence of an organic solvent an aromatic amine of the formula: ##STR2## with a tertiary hydroxyketone of the formula: ##STR3## wherein R, R.sub.1, R.sub.2 and R.sub.3 have the same meanings as defined above, in the presence of a catalyst selected from mineral acids, organic acids, Lewis acids or ionic exchange resins in acid form, and wherein said aromatic amine is slightly in excess, to form first an imine of the formula: ##STR4## under reaction conditions wherein the solvent is removed by azeotropic distillation, and thereafter continuing the reaction to remove water and cyclizing to the desired indolenines. In a preferred embodiment, 2,3,3-trimethylindolenine is prepared by reacting an excess of aniline with 3-methyl-3-hydroxybutan-2-one in the presence of ZnCl.sub.2 as catalyst utilizing benzene as solvent. The substituted indolenines obtained are useful in production of dyes and other compounds useful in the dyeing and photographic industries.