Extraktion von Naturstoffen mit überkritischen und verflüssigten Gasen

Zusammenfassung Eine Apparatur zur quantitativen Bestimmung der Löslichkeit im Mikromaßstab von Substanzen in überkritischen und verflüssigten Gasen wurde beschrieben. Hiermit konnte die Löslichkeit der Opiumalkaloide Morphin, Codein, Thebain, Papaverin und Noscapin in den Gasen Kohlendioxid, Distickstoffmonoxid und Trifluormethan ermittelt werden. Drücke zwischen 60 und 200 bar und Temperaturen zwischen 18 und 40° C wurden angewandt; die Löslichkeiten lagen je nach Alkaloid und Gas und den weiteren Bedingungen zwischen wenigeng und einigen mg pro Normalliter.

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Quantitative determination of the solubility of opium alkaloids

Summary An apparatus for the quantitative determination of the solubility of substances in supercritical and liquid gases on a micro scale is described. The solubilities of the opium alkaloids morphine, codeine, thebaine, papaverine, and noscapine in the gases carbon dioxide, nitrous oxide, and trifluoromethane were determined. With pressures of between 60 and 200 bar and temperatures between 18 and 40° C we found solubilities ranging between a fewg and mg per normal liter, depending on the alkaloid and the gas used as well as on further test conditions.

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5. Mitt.: Pharm. Ind. 42, 1136 (1980).     

The mass spectra of organic compounds. 7th Communication. 4,4-Dimethyl-1-pentene

Loss of CH, CH₄, C₂H₄, C₃H, C₃H₆ and C₃H₇ from the molecular ions of a number of ¹³C-labeled analogs of 4,4-dimethyl-1-pentene was studied both in normal (source) 70-eV electron impact (EI) spectra dn in metastable spectra. For loss of CH in the source, 96% of the methyl comes frm positions of 5, 5′ and 5″, while the remainder comes from position 1. In the metastable spectra, loss of C-1 (16%) and C-3 (9%) is increasing in importance. The loss of ethylene is a particular case: either C-1 or C-3 are lost with any other C-atom from positions 2,5,5′, and 5″ (8 × 10%) in the metastable spectra, the probability for simultaneous loss of C-1 and C-3 being 6%. If C-1 seems to these two positions become completely equivalent in the metastable time range. The T-values (kinetic energy release) for the different positions show small, but statisticaly different values and a small isotope effect. Loss of C₃H₅ (allylic cleavage) is 100% C-1, C-2 and C-3, i.e., no evidence for skeletal rearrangement is seen. This is also true for loss of C₃C₆ (McLafferty rearrangement) within the source, but in metastable decay the other positions gain in importance. The neutral fragment C₃H appears to be the the result of consecutive loss of CH and C₃H₄, rather than a one-step loss of propyl radical or the inverse reactions sequence. No metastable reaction can be seen for this reaction. Decomposition of labeled C₆H and C₅H secondary ions occurs in an essentially random fashion.     

Hydrogen transfer reaction on the surface of an oxide catalyst

RuO2(110) exposes two kinds of active surface species (acidic and basic centers) that govern the interaction of the gas phase in contact with the catalyst's surface. Here we will elucidate the cooperative interplay of these two active surface sites for a simple model reaction, namely the water formation over RuO2 catalysts when supplying hydrogen and oxygen from the gas phase. The bridging O atoms harvest the hydrogen from the gas phase, while the on-top O atoms pick up those adsorbed hydrogen atoms from the bridging O atoms to form water. This mechanism of hydrogen transfer is mediated by a strong hydrogen bond. Hydrogen transfer is expected to play a vital role for the whole class of catalyzed hydrogenation and dehydrogenation reactions of hydrocarbons over RuO2.     

A radical mechanism for the photochemical iron pentacarbonyl catalyzed hydrogenation of octenes

A high pressure IR and UV spectroscopic study of the catalysis of hydrogenation of 1-octene by Fe(CO)₅ under UV irradiation reveals that Fe(CO)₅ and (olefin)Fe(CO)₄ are the light absorbing species. The primary photolysis product Fe(CO)₄ reacts with H₂Fe(CO)₄ to give HFe(CO)₄ radicals, which are suggested to be the active hydrogenation promoters.     

Hyperelectronic polarization in macromolecular solids

Hyperelectronic polarization may be viewed as the electrical polarization in external fields due to the pliant interaction with the charge pairs of excitons, in which the charges are molecularly separated and range over molecularly limited domains. It is particularly pronounced in molecular solids composed of long polymeric molecules having extensive regions of electronic orbital delocalization. Hyperelectronic polarization is regarded as the principal contributor to the high polarizabilities of the following five macromolecular solids: four polyacene quinone radical polymers formed by condensation of aromatic hydrocarbon derivatives with aromatic acids and poly(Cu(II)-N,N′- dimethyl rebeanate). The first four polymers at 100 hz had dielectric constants of 1800–2400, decreasing to about 58–100 at 100,000 hz, with relaxation times of 10^?3 to 10^?4 sec. A sixth polymer, a Schiff-base condensate of 1,4-napthaquinone and p-toluene diisocyanate, however, showed little hyperelectronic polarization, displaying a dielectric constant of 10, constant over 100–100,000 hz. By simple arguments it is shown that the relaxation times and the frequency response of conduction are consonant with the proposed model of charges roaming over long molecular domains (up to 4000 A.) but restricted by molecular boundaries.