Abstract: A process for regulating at least one flow of at least one fluid or effluent circulating in a simulated moving bed comprising columns which form a closed loop containing at least one device such as a recycling pump introducing a pressure anisotropy. Every time an injection or extraction point passes from one part of the pump to the other, a control device which controls a fluid flow regulating means for the fluid under consideration, regulated about a set value, is caused to stop regulation temporarily, and substantially simultaneously the regulating means is placed in a position which allows it to approach the desired value, preferably to reach the desired flow rate and to begin to regulate the flow rate about the desired set value, to keep the flow rates in all the zones in a simulated moving bed constant. The process is especially applicable Application to the separation of para-xylene from a mixture of xylenes.

Abstract: In a simulated mobile bed separation process, perturbations are corrected in the compositions of an extract (EA) or raffinate (RB) due to the dead volume introduced by at least one recycling pump (P) or compressor for a liquid, supercritical or gaseous mixture in a closed circuit of columns.

Abstract: In a simulated mobile bed separation process, perturbations are corrected in the compositions of an extract (EA) or raffinate (RB) due to the dead volume introduced by at least one recycling pump (P) or compressor for a liquid, supercritical or gaseous mixture in a closed circuit of column sections. The volume of the section immediately upstream of the dead volume is reduced by an appropriate value when said dead volume is located downstream of this section and upstream of the extraction streams of said section, or the volume of the section immediately downstream of the dead volume is reduced by an appropriate value when the dead volume is located downstream of the injection streams into said section and upstream of this section.The invention is applicable to the separation of isomers of aromatic hydrocarbons containing 8 carbon atoms.

Abstract: A device for studying the behavior of a multiphase effluent in circulation includes a test pipe having two ends containing the effluent and a unit for delivering a working fluid alternately into each end of the pipe to effect movement of the effluent. The effluent to be studied which has been placed in the test pipe, is displaced according to an alternating circulation generated by injection of a working fluid into each of the ends of the pipe. A process for studying the behavior of the multiphase fluid in circulation involves placing the effluent in a test pipe, displacing the effluent in the test pipe in an alternating motion by delivering a working fluid alternately into each end of the pipe and measuring behavior of the effluent during the alternating displacement of the effluent.

Abstract: The invention concerns non-azeotropic fluid mixtures useful in compression thermodynamic cycles, for example in heat pumps, comprising R23, R142b and optionally a fluid (c) other than R23 or R142b, selected from the group formed of methane and ethane halogenated compounds having a boiling point from -85 to +60.degree. C., in such molar proportions that the R23/R142b ratio range from 0.01:1 to 1.10:1 and the (R23+R142b)/(R23+R142b +c) molar ratio from 0.26:1 to 1:1.The mixtures according to the invention can be used as working fluid for heat pumps whose fluid circulates through an evaporator (E.sub.1), a compressor (K.sub.1), a condenser (E.sub.2) and a pressure reducer (D.sub.1). The thermal exchanges take place respectively with external fluids (5,6) and (7,8).The mixtures according to the invention may supply heat to the condenser at a temperature from +50 to +100.degree. C. while having an internal pressure generally limited to 0.3 MPa.

Abstract: Aromatic polyimide compositions, useful in particular for manufacturing adhesive materials, varnishes and films withstanding high temperatures, having a high solubility in organic solvents, particularly polar solvents and which are manufactured by reacting, in such a solvent, a tetraester or diacid-diester of benzhydrol 3,3', 4, 4' tetracarboxylic acid with an aromatic diamine for a sufficient time to obtain a polycondensation reaction product having an inherent viscosity at 30.degree. C., at a concentration of 5 g/liter in N-methyl pyrrolidone, ranging from 0.1 to 2 dl/g.

Abstract: A hydrocarbon middle distillate contains an additive for decreasing its cloud point, obtained by reacting an aliphatic dicarboxylic compound selected from the maleic and alkylmaleic anhydrides, the alkenylsuccinic and polyalkenylsuccinic anhydrides and the corresponding dicarboxylic acids and lower alkyl diesters with a compound of the formula:R--Z--(CH.sub.2).sub.n NH].sub.m HorHO--CH.sub.2 --R.sup.5 --NH.sub.2wherein R is a monovalent saturated aliphatic radical, Z is NR' or O, R' being hydrogen or an aliphatic radical, n is an integer from 2 to 4, m is zero or an integer from 1 to 4 and R.sup.5 is a divalent saturated aliphatic radical.

Abstract: N-substituted succinimides are obtained by reacting in a first stage, maleic anhydride with an oxyalkylated or polyoxyalkylated monoalcohol of formulaR.sup.1 --O--A.sub.n OHwherein R.sup.1 is an aliphatic radical having from 12 to 25 carbon atoms, A is an alkylene radical having 2 to 4 carbon atoms and n is an integer from 1 to 50, and by further reacting the reaction product of the first stage either with a monoprimary amine of formulaR.sup.2 --X--Z.sub.m NH.sub.2or a bi-primary amine of the formulaH.sub.2 N--Z--NH.sub.p H,wherein R.sup.2 is an aliphatic radical having from 8 to 25 carbon atoms, Z is an alkylene radical having from 2 to 4 carbon atoms, X is --NH-- or --O--, m is an integer from 0 to 4 and p an integer from 2 to 6.The resultant succinimides are useful as anti-rust and detergent additives for motor fuels.

Abstract: A nitrogen-containing composition, useful as a detergent for gasoline, is obtained by reacting at least one unsaturated anhydride with at least one olefin to convert 20-80% of the anhydride and thereafter reacting the resultant product with a polyamine of the general formulaH.sub.2 N--[(--CH.sub.2 --)--.sub.n NH].sub.m R.sup.7wherein R.sup.7 is a monovalent aliphatic radical of 6-30 carbon atoms, n is an integer from 2 to 5 and m is an integer from 1 to 10.

Abstract: Alkyl-guanidino heterocyclic compound produced by alkylation with a halogenated hydrocarbon of the general formula RX.sub.n, of a guanidino-heterocyclic compound (A) of general formula: ##STR1## in which R is substantially a hydrocarbon radical containing about 10 to 200 carbon atoms, X is a halogen atom and n is 1 or 2; Y is an oxygen atom, --O--, a sulfur atom --S--, a --NH-- group, or a --CONH-- group in which the carbon atom is directly bound to the benzene ring, R' and R" are each a hydrogen atom, an alkyl radical having from 1 to 10 carbon atoms, or a --Z--Ar group in which Z is a divalent atom or group and Ar is a substituted or unsubstituted aromatic radical, R' and R" being capable of forming together, when they are in ortho position, an aliphatic or aromatic cycle fused to the benzene ring.

Abstract: Alkyl-guanidino heterocyclic compound produced by alkylation with a halogenated hydrocarbon of the general formula RX.sub.n, of a guanidino-heterocyclic compound (A) of general formula: ##STR1## in which R is substantially a hydrocarbon radical containing about 10 to 200 carbon atoms, X is a halogen atom and n is 1 or 2; Y is an oxygen atom, --O--, a sulfur atom --S--, a --NH-- group, or a --CONH-- group in which the carbon atom is directly bound to the benzene ring, R' and R" are each a hydrogen atom, an alkyl radical having from 1 to 10 carbon atoms, or a --Z--Ar group in which Z is a divalent atom or group and Ar is a substituted or unsubstituted aromatic radical, R' and R" being capable of forming together, when they are in ortho position, an aliphatic or aromatic cycle fused to the benzene ring.

Abstract: Alkyl-guanidino heterocyclic compound produced by alkylation with a halogenated hydrocarbon of the general formula RX.sub.n, of a guanidino-heterocyclic compound (A) of general formula: ##STR1## in which R is substantially a hydrocarbon radical containing about 10 to 200 carbon atoms, X is a halogen atom and n is 1 or 2; Y is an oxygen atom, --O--, a sulfur atom --S--, a --NH-- group, or a --COHN-- group in which the carbon atom is directly bound to the benzene ring, R' and R" are each a hydrogen atom, an alkyl radical having from 1 to 10 carbon atoms, or a --Z--Ar group in which Z is a divalent atom or group and Ar is a substituted or unsubstituted aromatic radical, R' and R" being capable of forming together, when they are in ortho position, an aliphatic or aromatic cycle fused to the benzene ring.

Abstract: A dicarboxylic compound complying with one of the general formulae: ##SPC1##In which R is a divalent radical selected from the aliphatic, alicyclic and aromatic radicals, the aliphatic containing 1-20 carbon atoms and the other containing from 5 to 20 carbon atoms, R.sup.1 is selected from the hydrogen atom and the alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms and R.sup.2 is selected from the alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms, the polyester resins derived therefrom being usable as enamelling composition, particularly for coating metal wires.

Abstract: New polyamide-ester resins, their manufacture and the new compositions manufactured therefrom, the latter being useful for enameling metal conductors. The enameled conductors are stable at relatively high temperatures.The resins are manufactured from a polycarboxylic component, a part of which is a 2,4-quinazoline dione dicarboxylic compound, a polyamine component and a polyhydroxy component.