The catalytic transfer hydrogenation of soybean oil by various hydrogen donors and solvents with palladium-oncarbon catalyst was investigated in batch and continuous modes. The choice of reaction conditions, donor and catalyst allowed the manufacture of partially hydrogenated oils or semi-solid fats with controlled fatty acid contents, iodine value, melting point and solid content index. The level of "iso" forms of fatty acids was similar to, and average initial selectivity was higher than that obtained with gaseous hydrogenation under pressure with a catalyst of the same type. The best results were obtained in aqueous solution with sodium formate as hydrogen donor at 60°C.

Electron ionization (EI),In the last few years several papers have dealt with the mass spectral differentiation of anomeric nucleosides,',2 g l y c~s i d e s~.~ and disac~harides.~, Fast-atom bombardment (FAB) mass spectra and spectra produced by FAB coupled with tandem mass spectrometry (MS/MS) of diastereoisomeric glycosylazide derivatives have been r e p~r t e d .~In the FAB spectra, pronounced fragment peaks were observed indicating the loss of hydrogen azide HN, from the protonated molecules. Differentiation between the azides studied is mainly based on the examination of collision-inducedfragment ions. Carbohydrate derivatives and some other organic azides have been investigated by desorption chemical ionization (DCI) and FAB.8 It was found that under these ionization conditions, the azido group can undergo reduction to an amino group. This was deduced from the appearance of an [MH-261' ion. This ion is formed after elimination of the nitrogen molecule from MH+ ions by subsequent reduction of the resulting [MH -N2]+ ions by hydrogen radicals in the ion source.'These studies have shown that the fragmentation patterns of several organic azides can differ widely, depending on the mass spectral technique used. However, there are many examples showing that it is possible to distinguish the anomers unambiguously by mass spectral methods.Here we report a mass spectral investigation of anomeric 2,3-@isopropylidene a-and 0-D-ribofuranosyl azide derivatives, configurations of which are depicted below. The compounds la, lb, 5a and 5b are important synthetic starting azides to be transformed, for example, into triazolo ribonucleo~ides.~ To establish the origin of the most important ions appearing in the electron ionization (EI) mass spectra of l a and l b their deuterium-labelled derivatives (2-4) have also been examined. EXPERIMENTALThe syntheses of compounds 1 and 5 have been describedpreviously . 92,3-0-Isopropylidene (hexadeuter0)-Author to whom correspondence should be addressed. $H,OR' CH2OR'COC&jNOZ-p CH3 Sb a-D-ribofuranosylazide (3a) and 2,3-@isopropylidene-(hexadeuter0)-P-D-ribofuranosyl azide (3b) were prepared by the I2 catalyzed procedure" using hexadeuteroacetone in more than 80% yield as colorless liquids. Compounds 2 and 4 were obtained by hydrogendeuterium exchange in the hydroxyl group of 1 and 3, respectively. This was done by repetitive adding (and drying) of D 2 0 to the sample in the probe capillary.All mass spectral measurements were performed with an AutospecQ mass spectrometer of EBEqQ configuration (Fisons, VG Analytical, Manchester, UK). The samples were introduced via a direct-sample probe. Ammonia chemical ionization (CI) was carried out at an ammonia gas pressure that resulted in great excess of [NH,]' relative to [NH4NH3]+. The pressure conditions in methane CI were such that nearly equal amounts of CH; and C2H; were produced. RESULTS AND DISCUSSION EI mass spectraThe EI mass spectra of 1 to 4 are presented in Fig, 1 and those of the anomers of 5 in Fig. 2. The origin of the most importan...

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