The extraction of coal with supercritical hydrocarbon mixtures

The National Coal Board has developed a process for converting coal into distillable liquids based on the extraction by supercritical fluids of fragments of coal molecules produced by thermolysis. The resultant coal extract has desirable properties for subsequent hydroprocessing. This paper outlines process requirements and describes how these were realised in a 10 kg h⁻¹ pilot plant. Results illustrating the effects of main process variables are given, using examples taken from experimental work employing a simulated process-derived solvent as extractant. Yields and analyses are presented for products obtained under varied processing conditions.     

Gamma ray and π0 production from hydrogen and complex nuclei by 270–375 MeV gamma rays

Measurements are reported on the differential cross section for secondary gamma ray production on hydrogen and nuclear targets at 90° in the laboratory through the interactions of primary gamma rays in the energy range 270–375 MeV. A difference method using bremsstrahlung beams at different end point energies was employed. The gamma ray detector was a high resolution Nal(Tl) spectrometer and time of flight discrimination was used to reject neutrons. For incident gamma rays in the range 270–375 MeV the first pion nucleon resonance is strongly excited and the observed gamma ray yields are consistent with those expected due to an admixture of coherent and incoherent π⁰ photoproduction in the resonance region. The experiment marks the first successful use of a large Nal(Tl) crystals as a gamma ray spectrometer at a high energy electron linear accelerator, despite the low duty cycle and its accompanying difficulties for such detectors.     

Measurement of differential cross sections for elastic K+p scattering in the momentum range 0.7 to 1.9 GeV/c

Differential cross sections for elastic K⁺p scattering have been measured at nineteen momenta between 0.7 and 1.9 GeV/c. The data represent between 10 thousand and 20 thousand elastic events at each momentum and cover a wide range of scattering angles ($\text{?0.98 ?}\text{cos}\text{θ}{}^1\text{? 0.95}$). A computer controlled system of scintillation counters and acoustic spark chambers was used to detect the elastic events. Various internal consistency checks indicate that the absolute normalization of the data is accurate to within 2–3%. The cross sections show a smooth transition from an isotropic angular distribution to a dominant forward peak over the range covered by the experiment. Phase-shift analyses including these results show little evidence for a direct-channel resonance, and fitting the results by t- and u-channel exchange processes alone gives a good fit.     

An asymmetric synthesis of (+)-kjellmanianone

Racemic and asymmetric syntheses of kjellmanianone, a novel cyclopentenoid antibiotic, are described.     

The preparation of octahydro leukotrienes C,D, and E via a stereoselective sulfenyllactonization reaction

Sulfenyl halides derived from the N-trifluoroacetamido methyl ester derivatives of cysteine, cysteinyiglycine and glutathione react stereoselectively with (5E)- and (5Z)-eicosenoic acids to provide, after separation of diastereomers and hydrolysis of the protecting groups, the fully saturated analogues of leukotrienes LTC₄, LTD₄, and LTE₄.