Investigation of polysaccharides by two-dimensional N.M.R. Spectroscopy

Summary This paper is relative to a study of polysaccharides in solution by two-dimensional nuclear Overhauser enhancement (2D NOE) and correlated (SECSY) experiments. The main advantages and limitations of these techniques are described in the case of molecules in solution into dimethyl sulfoxide (d.m.s.o.). In particular only one 2D NOE experiment is capable to provide informations concerning dipolar interactions as well as chemical exchange phenomena. It also open a new route to obtain conformational data with polysaccharides.Laboratoire Propre du C.N.R.S., Associé à l'Université Scientifique et Médicale de Grenoble     

N.M.R. Studies on Aminated Dinitrobenzofuroxan and Dinitrobenzofurazan Derivatives

The ¹³C-n.m.r. chemical shifts of σ-N C-bonded Meisenheimer complexes 3 , 5 and their corresponding aminated dinitrobenzofurazans 4 and dinitrobenzofuroxans 6 were determined. The chemical shifts are discussed as a function of electronic substituent effects. The assignment was performed by means of ¹H ¹³C coupling constants and by comparison with che ¹³C-chemical shifts of appropriate model compounds. The ¹³C-n.m.r. spectra of Meisenheimer tomplexes 3 reveal doubling of signals, indicating a hindered rotation at the N CHO bond.     

The chemical nature of flash pyrolysis tars. An N.M.R. study

Flash pyrolysis tars from one brown and two bituminous Australian coals were separated into oils, asphaltenes and pre-asphaltenes. The oils were further separated by chromatography while the asphaltenes were separated into basic and acid/neutral fractions. The pre-asphaltenes were silyalated prior to ¹³C- and ¹H-n.m.r. studies. The brown coal tar was less aromatic and contained more long alkyl chains than the tars from the bituminous coals. Aliphatic constituents of the oils, which were relatively abundant, consisted mainly of n-alkanes and straight chain 1-alkenes with an average chain length of ca. C₁₃. The pre-asphaltenes were no more aromatic than the asphaltenes from the same tar but had higher molecular weights.     

DRYING R D IN THE F.R. GERMANY

This paper summarizes the developments in the field of drying within the Federal Republic of Germany. The main areas on the scientific side (software) as well as those on the manufacturing'side (hardware) are discussed. This survey covers the period, 1976-1986.

On the theoretical side, research and development activities have focussed on convective and contact drying, modelling of contact dryers, selective drying of products with solvents, drying of mixtures and relevant topics in the field of ad-and desorption. On the hardware side, design to fit a changing framework (environment, energy, legislation, etc.), integration of up-and downstream equipment, detail improvements and new types of dryers (as well as applications of otherwise known equipment to drying) have been the major developments. A list of West German manufacturers of drying equipment is also in-cluded as an Appendix.     

DRYING R D IN THE F.R. GERMANY

This paper summarizes the developments in the field of drying within the Federal Republic of Germany. The main areas on the scientific side (software) as well as those on the manufacturing'side (hardware) are discussed. This survey covers the period, 1976-1986.

On the theoretical side, research and development activities have focussed on convective and contact drying, modelling of contact dryers, selective drying of products with solvents, drying of mixtures and relevant topics in the field of ad-and desorption. On the hardware side, design to fit a changing framework (environment, energy, legislation, etc.), integration of up-and downstream equipment, detail improvements and new types of dryers (as well as applications of otherwise known equipment to drying) have been the major developments. A list of West German manufacturers of drying equipment is also in-cluded as an Appendix.     

Substituent Effects on the N. M. R. Signals of the Angular Methyl Groups in Steroids

The chemical shifts of the angular methyl groups in 131 steroids are tabulated and discussed. Additivity increments of substituents mainly at positions 1, 4, 5 and 6 are derived.     

Seventieth birthday of N. M. Pavlushkin

Information

Seventieth birthday of N. M. Pavlushkin     

Simulation of M.S.F. desalination plants

A simulation program on the modeling of MSF desalination plants has been developed by the author (ref. 1). The program can be used to accurately either design or simulate plants in actual operation. Proprietory computer programs have been originated by a number of desalination designers for their own use. A few general ones have been published (refs. 2 & 3).The paper describes the design and modeling philosophy utilized in developing the said program. A typical application on Al-Khobar (Phase-I) MSF desalination plant is briefly illustrated as an example for the use of simulation mode of the code.