E. Kozlova

Biocatalytic resolution of β-fluoroalkyl-β-amino acids

Abstract N -Phenylacetyl derivatives of β-fluoroalkyl-β-alanines 6 were synthesized and biocatalytically resolved to the corresponding enantiopure β-amino acids 7,9 with the aid of penicillin acylase (EC 3.5.1.11) from Escherichia coli . In substrates 6 the enantioselectivity of the biocatalytic process was practically uninfluenced by the nature of the fluoroalkyl chain. Thus, β-fluoroalkyl-β-alanines 7,9 bearing short (R = CF 3 , CHF 2 ) or long [C 3 F 7 , H(CF 2 )4] chains were prepared in high enantiomeric parity. The ( R )-enantiomer was the fast-reacting enantiomer in all cases.

First sampling of gas hydrate from the Vøring Plateau

Methane hydrate is a clathrate, an ice-like solid formed from methane and water, that is stable under conditions of pressure and temperature found in most of the worlds oceans at depths greater than a few hundred meters. Hydrate occurs beneath the seabed where there is sufficient methane to exceed its solubility in water within the hydrate stability field. It has been speculated that methane released from hydrate by climate-induced changes in pressure and temperature escapes into the ocean and into the atmosphere, where its acts as a greenhouse gas. Further, methane from beneath the seabed is the primary energy source for communities of chemosynthetic biota at the seabed.

Enzymatic preparation of both L- and D-enantiomers of phosphonic and phosphonous analogues of alanine using penicillin acylase

Abstract D-Enantiomers of N-acylated 1-aminoethylphosphonic and 1-aminoethylphosphonous acids were able to be hydrolyzed with high concentrations of penicillin acylase in a reasonable time period. This finding was used to prepare both L- and D-enantiomers of these phosphorus analogues of alanine by stepwise enzymatic hydrolysis of their racemic N-phenylacetyl derivatives using the same enzyme - penicillin acylase - by simply changing the enzyme/ substrate ratio.

New discoveries of mud volcanoes on the Eastern Mediterranean Ridge

Data from two mud volcanoes discovered on the eastern Mediterranean Ridge are presented, showing that these features have erupted episodically within historical time. Both volcanoes mark the site of active gas and fluid venting from deep within the sedimentary pile. Large volumes of mud breccia have been extruded onto the volcano slopes. For the first time, clasts up to c. 1 m in size have been recovered from sea-floor mud volcanoes. The submarine clasts show lithologies ranging from shallow water bioclastic sandstones to marls and limestones, dated using microfauna as Oligocene, Miocene and perhaps Cretaceous in age. Deep-towed video footage of one of the volcanoes shows clasts up to several metres across within the crater area. Deep-towed, high resolution side-scan sonar data and core data are presented to compare the two examples. The paper documents the discovery of the two volcanoes: the Dublin mud volcano and the Stoke-on-Trent mud volcano, the clasts that have been recovered from them, the intermittence of the eruptions as interpreted from gravity-core data, and how the volcanoes contrast with other mud volcanoes further to the west.

Rock fragments from mud volcanic deposits of the Gulf of Cadiz: An insight into the Eocene-Pliocene sedimentary succession of the basin

Abstract Two hundred clasts from the mud breccia extruded by the Yuma mud volcano in the Gulf of Cadiz are used to establish an offshore stratigraphy. The clasts are a very complex mixture of material from the sedimentary successions through which the mud volcano erupted and provide important information about the composition and genesis of deep-seated strata. We deal with fragments of rocks that were deposited millions of years ago, subsequently buried and later erupted on to the seafloor. Rock fragments from the mud breccia, studied in thin section under a polarizing microscope, provide genetic indications suggestive of deep-sea conditions during the accumulation of strata. A reconstruction of the sedimentary succession through which the Yuma mud volcano erupted and the depositional evolution of the Gulf of Cadiz was made on the basis of lithology and age determinations of the rock. Age and depositional environment documented by the clasts indicate that a marine basin existed in the Gulf of Cadiz area at least from the Eocene, and that in the Early and Middle Eocene a deep-sea fan depositional environment prevailed in the region, resulting in the accumulation of thick turbidites. The Late Eocene and Oligocene are not represented among rock fragments from the mud breccia, suggesting regional uplift and non-deposition in the area. Sedimentation was re-established in the Miocene with the accumulation of a clayey Aquitanian–Burdigalian succession. Pelagic carbonate sedimentation became predominant in the Langhian time. The Serravallian–Early Tortonian is characterized by a high supply of terrigenous material, resulting in the deposition of turbiditic clays and sands. Shallow water sedimentation with accumulation of carbonate rocks prevailed in the basin during the Middle Tortonian.

Experimental investigations of hydrocarbon fluid recovery from hydrothermally treated rocks of the Bazhenov Formation

The results of experimental shale-oil recovery from hydrothermally treated rocks of the Bazhenov Formation are discussed. It is shown that the yield depends on the duration of an experiment: the longer the hydrothermal impact is, the higher the oil yield is. The potential of oil recovery from hydrothermally treated rocks of the Bazhenov Formation is as high as 25 mg/g or 2.5 wt %. The addition of reducing agents such as aluminum or oxalic acid provides no increase in the coefficient of oil recovery. It is established that the yield of the oil fraction at 250°C is insignificant; at 300°C, it amounts to 25 mg/g, while at 350°C, it decreases up to 15 mg/g. This means that a temperature of 300°C is preferable, since it provides a higher yield of oil products and oil fractions are largely represented by normal alkanes, while chromatograms that were obtained at 350°C indicate the development of complex processes, including graphitization of kerogen.

Geochemical technique of organic matter research in deposits enrich in kerogene (the Bazhenov Formation, West Siberia)

The international interest in shale oil has recently provoked special attention to the Russian unconventional oil-source formations, including the Bazhenov Formation of West Siberia, domanik deposits in the Volga–Ural region, and the lower Maikop Group of the Cis-Caucasus. High contents of para-autochthonous soluble organic matter (bitumen) in clayey–carbonate, clayey–siliceous, carbonate–clayey–siliceous rocks with low filtration–capacity properties results in significant uncertainties in the identification of the generation potential of organic matter (OM). Examination of a large database on the OM of the Bazhenov Formation allowed us to propose an optimum complex technique for study of the source rock potential and assessment of the amount of produced hydrocarbons in the kerogen-rich sediments. The investigations include a combination of Rock Eval pyrolysis prior to and after extraction with different solvents, the comparison of bituminological and pyrolytic characteristics, and the determination of the group composition of soluble organic matter, as well as chromatography and chromato-mass spectrometry.

Proof of formation of organic matter in upper Devonian carbonate and carbonate-siliceous sediments of the South-Tatar uplift in constant photic layer anoxia

Samples of carbonate and siliceous-carbonate deposits of Semiluk—Sargaev horizons of the N‒NE slope of the South Tatar uplift, Volga-Ural petroliferous basin, have been studied. Specific feature of the source rocks—high concentration of compounds—anoxia testifiers in the photic layer has been identified. That is, organic matter has been deposited under the conditions of the constant presence of anoxia in the photic layer of the sedimentation basin at sufficiently high thickness of the water column contaminated with hydrogen sulfide. Since by the composition of saturated hydrocarbons the studied samples are typical for deposits of the Semiluk horizon of the central part of the Volga-Ural basin, we can assume a fairly wide prevalence of such conditions within the South-Tatar arch. Changes in the concentrations of the components—anoxia markers—show cyclical changes in output layer contaminated with hydrogen sulfide or its bioproduction within the studied time.

The hydrocarbon-generation potential of the Domanik rocks in the Volga–Ural petroliferous basin

The factors that are responsible for the formation of the hydrocarbon-generation potential and its occurrence in the Devonian carbonate sequences (Domanik Formation) of the Volga–Ural petroliferous basin are considered. The rocks of this formation are characterized by a high generation potential that is sufficient for the formation of large oil and gas accumulations. The highly carbonaceous deposits lack reservoirs.

Cenozoic complex in the Upper Telekai oil-and-gas field in the Chukchi Peninsula (results of petrographic examination of the succession penetrated by well 10)

The paper discusses new data resulting from petrographic examination of the composition and structure of Cenozoic sediments penetrated by Well 10 to a depth of 2350 m in the Upper Telekai oil-and-gas field within the Anadyr Basin. An alluvial-deltaic sedimentation environment of tuffaceous-sedimentary and terrigenous producing Lower Miocene rocks was found and their secondary alterations examined, including formation of clay minerals, carbonates, and zeolite. The vitrinite reflectance indices allowed determination of the catagenic zoning of the Miocene succession, and a significant catagenic unconformity related to pre-Pliocene erosion was recorded at its top.