Reaction of cyanuric chloride and its derivatives with polyamide fibres in non-aqueous medium

Polyamide fibres (Nylon 6) were treated with cyanuric chloride in organic solvents (tetrachloroethylene and xylene) under different conditions. This treatment caused an increase in the fibre nitrogen content. The magnitude of the latter was dependent upon the cyanuric chloride concentration, the time and temperature of the treatment as well as the nature of solvent. For instance an extra nitrogen content of 0.08% was obtained at a cyanuric chloride concentration (based on wt. of fabric) of 25%. This contrasts with 0.46% at 100% concentration of cyanuric chloride. Similarly and extra nitrogen content of 0.08% was achieved at 50°C while at 121°C it amounted to 1.18%. However, the cyanuric chloride treated nuylon failed to link covalently to dyestuffs containing labile hydrogen, indicating no chemical reaction between polyamide 6 and cyanuric chloride. This chemical reaction could only be achieved by use of 2-anilino-4,6-dichloro-1,3,5-triazine instead of cyanuric chloride. Similarly a disperse dye containing a chlorotriazine ring as the reactive group was found to react chemically with polyamide 6.     

Intensification of the use of ionic liquids as efficient reaction co-solvents in asymmetric hydrogenations

The “Noyori” Ru-BINAP chiral complex is an industrially used homogeneous catalyst for stereoselective hydrogenations providing valuable fine chemicals with high optical yields. Its pseudo-immobilisation with help of various ionic liquids (ILs) represents an alternative to the not very efficient heterogenisation on inorganic supports. Many ILs are commercially readily available or could simply be produced, but in both cases a problem of their purity is encountered. Presence of even trace impurities may either suppress or promote the reaction progress, and most importantly, the parameter of enantioselectivity. The complex treatment of the reaction system must be always accepted whenever a genuine role of an ionic liquid is discussed. For this purpose a well understood reaction system—asymmetric hydrogenation of methyl-3-oxobutanoate (methylacetoacetate/MAA) to methyl-3-hydroxybutanoate (methylhydroxybutyrate/MHB) over the chiral Noyori type Ru-BINAP catalyst in the ethanol-bmimPF₆ reversibly biphasic mixed phase was chosen. Self-prepared bmimPF₆ ionic liquid was exposed to a series of normalized purification steps based on a theoretical semi-mechanistic model. It provided a clear evidence of the number and duration of necessary purification steps together with an effective “value” of each of them. Another important data were collected in the form of pseudo-ternary phase diagrams for all major components including the model impurities.     

A MONTE-CARLO APPROACH TO THE INTERPRETATION OF BUBBLE PROBE SIGNALS IN FREELY BUBBLING FLUID BEDS†

The interpretation of the signals generated by a double probe may be done by the three characteristic times method:

t₁ the time duration of the pulses;

t₂ the time shift between the signals of the two probes;

t₃ the time interval between two pulses on one channel.

Each of these times is largely dispersed and the corresponding histograms may be constructed.

The present work is a trial to go over from the time histograms to physical properties of the bubbles combining a Monte-Carlo simulation and a flexible simplex optimisation procedure.

As a result, the percentage of oblique bubbles cutting just one level, the bubble size distribution, the average velocity-size relation, and the individual dispersion around it may be defined.

The procedure is finally applied to experimental results obtained with a light probe in a fluid bed of glass beads.     

BUBBLE TEMPERATURE MEASUREMENTS ON THE BINARY MIXTURES OF 1,4-DIMETHYLBENZENE WITH ISO -, SEC -, AND TERT - BUTANOLS AT 95 kPa

Bubble temperatures at 95 kPa over the entire composition range were measured for the three binary systems formed by 1,4-dimethylbenzene with iso-, sec-, and tert- butanols. A Swietoslawski-type ebulliometer was used for the measurements. The composition versus temperature measurements are well represented by the Wilson model.     

KINETIC THEORY OF FLOW IN STRONGLY INHOMOGENEOUS FLUIDS

Enskog's kinetic theory of dense hard sphere fluids, modified to allow long-ranged attractive interactions in a mean field sense, is solved for the case of slow flow in strongly inhomogeneous fluids, such as fluids near solid surfaces or liquid-vapor interfaces. In the equilibrium limit the theory yields the exact Yvon-Born-Green equation for the density distribution. In the slow flow limit the viscosity is a tensorial functional of the density distribution. Expressions for the velocity profile are derived for plane laminar and Couette flows. The density dependence of the transport coefficients is smoothed once through the angle averaging of the binary collisions of the Enskog theory. In the planar flows the velocity profile obeys a second order differential equation with variable coefficients and so the density dependence is further muted by two successive spatial integrations. The result leads one to expect the velocity profile to depend relatively weakly on density variations. This conclusion is in agreement with recently available computer simulations of flow in micropores. Another conclusion of the work is that one cannot introduce a flow or pore size independent effective viscosity to describe flow in micropores.