摘要:
An improved isobaric double-recycle process is disclosed for synthesizing urea with the formation of ammonium carbamate as an intermediate, comprising effecting reaction between ammonia and carbon dioxide at high NH.sub.3 :CO.sub.2 molar ratios, a heat-treatment of the synthesis product at substantially the same pressure as that of the synthesis step and in the presence of a stripping gas, and two distinct isobaric recycles of the residual substances and of the substances in excess released from said synthesis product, said process being characterized in that:(a) said heat-treatment of the synthesis product is carried out in two consecutive stages which are isobaric or substantially isobaric with respect to the synthesis step, in the first of which stages said synthesis product is heated, whereby substantially all the residual ammonium carbamate is decomposed and the decomposition products are displaced together with part of the excess NH.sub.3, while in the second stage the remaining part of the NH.sub.3 excess is displaced by supplying supplemental heat and by injecting thereto a CO.sub.2 stream; and(b) the gas phase stripped in the first stage is immediately recycled to the synthesis step and the gas phase stripped in the second stage is subjected to a condensation and to a residual gas purge and then recycled, in the liquid state, to the synthesis step.The synthesis temperature may range from 170.degree. to 205.degree. C., the synthesis pressure from between 100 and 250 Kg/cm.sup.2, and the NH.sub.3 :CO.sub.2 molar ratio during the synthesis from 2.5:1 to 10:1.Suitable apparatus for carrying out the process is also disclosed.
摘要:
The invention concerns impact resistant polymeric compositions having flame-resistance properties and comprising:(1) a blend of (a) 95-80% by weight of a thermoplastic block propylene-ethylene copolymer containing from 3 to 20% by weight of copolymerized ethylene, and(b) 5-20% by weight of an elastomeric ethylene-propylene copolymer containing from 50 to 70% by weight of copolymerized ethylene;(2) 0.5-5% of basic bismuth carbonate (BiO).sub.2 CO.sub.3 ;(3) 0.3-1.3% of a triazine compound selected from the group consisting of melamine, ammeline, ammelide, acetoguanamine, benzoguanamine and isocyanuric acid;(4) 2-10% of a chlorinated paraffin wax; and(5) 0.5-10% of a bromine containing organic compound selected from the group consisting of decabromodiphenyl oxide, octabromodiphenyl oxide, pentabromodiphenyl oxide, 1,2-bis(2.4.6-tribromophenoxy)ethane, pentabromophenol, pentabromotoluene and ethyl-pentabromobenzene;all percentages of anti-flame additives being referred to the total weight of the composition.The foregoing compositions are useful in the manufacture of motor vehicles.
摘要:
The present invention concerns new propellant compositions for aerosols. More particularly, the propellant compositions of this invention consist of a mixture of one or more propelling hydrocarbon substances selected from the group consisting of propane, n-butane, isobutane, pentane and isopentanes with one or more halogenated organic compounds selected from the group consisting of CBrF.sub.3, CBrClF.sub.2 and CBrF.sub.2 -CBrF.sub.2.
摘要:
A process is disclosed for preparing esters having the general formulae:RCOOCH.sub.2 R'andR'COOCH.sub.2 Rwherein R and R' are linear or branched alkyl radicals either like or unlike each other, and containing from 1 to 16 carbon atoms, or considered together, forming a cycloaliphatic ring having up to 7 carbon atoms, wherein carbon monoxide and hydrogen are reacted, at temperatures ranging from 150.degree. to 350.degree. C. and at pressures ranging from 50 to 1000 atmospheres, with an ether of formula R O R' or esters of formula RCOOR' and R'COOR, in which R and R' have the same meanings as specified hereinabove, and in the presence of a catalyst system comprising a ruthenium carbonyl and a promoter selected from the class consisting of hydroiodic acid, carboxylic acid solutions of inorganic or tetraalkylammonium bromides and iodides, and mixtures of these promoters.
摘要:
Ethylene is polymerized in a gaseous phase and in contact with a Ziegler/Natta type solid catalyst capable of producing polyethylene in the form of granules having an easily controllable and homogeneous granulometric size, the polymerization being conducted in a tubular reactor in which the catalyst and the polymer granules which are formed are carried along the reactor by the flow of the gas.
摘要:
This invention relates to a class of water-soluble acid azo dyes, containing at least a sulphonic group, having formula (I): ##STR1## wherein the symbols have the following meanings: A is a residue of a diazotizable aromatic or heterocyclic amine, optionally substituted;R is selected from the group consisting of H, CH.sub.3, OCH.sub.3 and OC.sub.2 H.sub.5 ;R.sub.1 is selected from the group consisting of CH.sub.3 and C.sub.2 H.sub.5 ;R.sub.2 is selected from the group consisting of CH.sub.3 and C.sub.2 H.sub.5.The dyes which are the object of the present invention exhibit shades varying from yellow to blue and are useful for dyeing and printing natural polyamide fibres (wool and silk) and synthetic fibres (nylon). They possess an excellent affinity in both an acid bath and a neutral bath and an excellent tinting power. The dyes obtained are characterized by a remarkable purity of shade, by an excellent stability to sunlight, to washing and to sweat, as well as by a good equalizing power on nylon.
摘要:
Process and apparatus are disclosed for the preparation of sulphur hexafluoride of high purity, starting from elemental fluorine and sulphur, both in gaseous phase, and operating with an excess of fluorine, characterized in that the fluorine is fed into a reaction chamber through inlets in a metal plate, maintained at between 30.degree. and 70.degree. C., while the sulphur is fed in through the nozzle of a burner, by regulating a current of an inert gas which is saturated with sulphur by passing same through a zone containing molten sulphur at a temperature between 250.degree. and 500.degree. C., and subsequently superheating the inert gas thus saturated with sulphur to a temperature between 300.degree. and 550.degree. C., and introducing a separate current of the same inert gas between the plate and the burner so as to ensure that the flame that develops when the sulphur and the fluorine come into reactive contact with each other shall be kept insulated from the nozzle, and recovering and purifying the resulting sulphur hexafluoride.
摘要:
Benzimidazol(2)methylcarbamates substituted in position 5(6) are disclosed, together with a method for preparing them, and use thereof in suitable form for combatting intestinal, pulmonary and hepatic parasites, particularly Helminthes, in animals.
摘要:
A new class fluorosulphonyl oxafluoroalkanes and of their derivatives is disclosed as well as a process for preparing said products. Furthermore, a new class of fluorosulphonyl olefins, copolymers thereof and a process for preparing same is also disclosed.
摘要:
The present invention concerns new propellant compositions for aerosols. More particularly, the present invention relates to propellant compositions for aerosols, characterized in that said compositions consist of a mixture of a chlorofluorocarbon or fluorocarbon (A) containing hydrogen and selected from the group consisting of CHClF.sub.2, CH.sub.2 F.sub.2 and CF.sub.3 --CH.sub.3, with a chlorofluorocarbon or fluorocarbon (B) containing hydrogen and selected from the group consisting of: CH.sub.2 ClF, CClF.sub.2 --CHClF, CF.sub.3 --CHClF, CHF.sub.2 --CClF.sub.2, CHClF--CHF.sub.2, CF.sub.3 --CH.sub.2 --Cl, CHF.sub.2 --CHF.sub.2, CF.sub.3 --CH.sub.2 F, CClF.sub.2 --CH.sub.3 and CHF.sub.2 --CH.sub.3. In addition to propellant A and propellant B, there may be included a hydrocarbon propellant so that a ternary propellant composition is provided.