The isolation and characterization of new lanthanide complexes of formula [Ln(Q(L))(3)(EtOH)(H2O)], (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, HQ(L) = 1-phenyl-3-methyl-4-phenylacetylpyrazol-5-one) [Ln(Q(L))(3)(H2O)(2)] (L = La or Lu), [Ln(Q(S))(3)(EtOH)(H2O)] (Ln = Tb or Eu; HQ(s) = 1-phenyl-3-methyl-4-thienoylpyrazol-5-one, [Tb(Q(o))(3)(EtOH)(H2O)] (HQ(o) = 1-phenyl-3-methyl-4-furanoylpyrazol-5-one) [Tb(Q(F))(3)(H2O) (HQ(F) = 1-phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one) and [NBu4][Ln(Q)(4)] (Ln = Eu or Tb, Q = Q(F) or Q(L)) is reported. The crystal structure of the tris(beta-diketonate) complexes [Nd(Q(L))(3)(EtOH)(H2O)], [Dy(Q(L))(3)(EtOH)(H2O)](EtOH), and [Eu(Q(s))(3)(H2O)(EtOH)] containing eight-coordinate lanthanide ions in a square antiprismatic environment has been determined. The coordination environment in the tetrakis complex [NBu4][Eu(Q(F))(4)] is also close to the square antiprismatic one. Photoluminescence (PL) and phosphorescence studies of selected derivatives are reported
Phosphorescence of methyl acetate formed by isomerization of electron-excited dimethyldioxirane is observed upon excitation at the wavelength of the absorption band of dimethyldioxirane in acetone at 77 K. The quantum yield of the photodeeomposition of dimethyidioxirane at 296 K is equal to 13.1+0.7 tool Einstein -l. The high quantum yield of photolysis is evidence for the chain mechanism of decomposition of dimethyldioxirane.
The decomposition of dimethyldioxirane (1) in oxygen-free acetone solutions (46 ~ is accompanied by chemiluminescence (CL) in the visible spectral region. The emitter of CL is triplet-excited methyl acetate (2"('I')). For the decomposition of solutions of I in acetone and deuterated dimethyldioxirane in acetone-D 6 the decay of CL follows the first-order kinetics, and the kinetic isotope effect is observed. Two mechanisms of the formation of 2*(T) are discussed: ta) chain-radical process and (b) isomerization of 1 to 2.Key words: organic peroxides, dimethyldioxirane, chemiluminescence, mechanism of chemiluminescence.Formation of excited products in the decomposition accompanied by chemiluminescence (CL) is a general property of several cyclic peroxides. For example, the decomposition of dioxetanes gives ketones in singlet and triplet excited states, i,2 and the decomposition of some ozonides results in the formation of singlet oxygen. 3,4 In the majority of cases, these are precisely the products which are emitters of the luminescence appeared. Cyclic peroxides (dioxiranes 5,6) are not exceptions in this series. The energy released in the decomposition of dioxiranes to the corresponding ester is equal to -80 kcal real -1 al~d, hence, a chemiluminescence process is possible. 5,r In fact, we have shown 8 that the thermal decomposition of dimethyldioxirane (1) in the presence of an activator of CL, 9,10-dibromoanthracene (DBA), results in the appearance of CL caused, as we supposed, by the energy transfer from triplet-excited methyl acetate (2*(T)) (the main product of the decomposition of 1) to DBA. Later, 9 we observed a substantially more intense CL in the decomposition of compound 1 sorbed from the gas phase on the surface of Sitipor. However, zao CL was observed in a solution of i in acetone. We related this fact to the quenching process and, first of all, to the presence of oxygen, an efficient quenching agent of triplet-excited states. In this work, we first report on CL in the thermal decomposition of oxygenfree solutions of 1 in acetone. ExperimentalDioxirane 1 was obtained and analyzed as described in Ref. 10. The kinetics of the decomposition of 1 was monitored spectrophotometrically in a thermostated quartz ceil (the opti-" Dedicated to Prof, W. Adam on the occasion of his 60th birthday.cal path was 1 cm) by the decrease in the optical density at L 335 nm (e 10 L real -I cm-t) t~ on a Specord M-40 instrument (Carl Zeiss, Jena). Chemiluminescence was monitored on an installation of an FEU-140 photomultiplier calibrated in absolute units according to a procedure described previously. It Phosphorescence spectra of methyl acetate (2) were recorded on a Hitachi MPF-4 spectrofluorimeter at 77 K. Oxygen from a solution of 1 in acetone was removed by subsequent "freezing-evacuating-thawing out" procedures repeated 5--6 times until the release of gas bubbles stopped completely. After this, a solution of I in acetone was placed in a therrnostated cell arranged above the photocathode of the photomultiplier, and CL ...
Yukos Oil Company is the second largest oil production company in Russia, and produces 1.2 million barrels daily, with > 60% of this coming from fields in W. Siberia. Base oil and gas production units are located in the European part of Russia (OAO Samaraneftegaz) and W. Siberia (OAO Yuganskneftegaz and OAO Tomskneft VNK) [1]. This production comes from a variety of fields, and it is common for these fields to produce at significant water cuts. Produced water leads to several production and cleanup problems (since it is also re-injected), one of these being the problem of mineral scale. The most common scale is calcium carbonate and this is found in both mild and more severe scaling cases. Sulfate deposits are present too in minimal amounts. However, a feature of the W. Siberian reservoirs is that they have many thousands of wells. Therefore, although the technical problem of treating a single well may not be large, the approach and logistics to protect such a large number of wells is a significant challenge. In this paper we survey the problems of scale in these W. Siberian fields and we outline how Yukos has approached this challenge. Introduction Two production units, OAO Tomskneft and OAO Yuganskneftegaz, carry out the main oil production in Western Siberia on the territory where Yukos has licenses. Fig.1 shows the geographical placement of Yukos's main production and refining units. A brief description of them is presented below. OAO Tomskneft VNK. OAO Tomskneft VNK is the principal Production Association of Yukos subsidiary OAO "Vostochnaya nefteyanaya kompanya", also known as VNK or the Eastern Oil Company. Established in 1966, Tomskneft VNK has produced more than 2 billion barrels of oil since it began its operations. 21 fields are currently under development or in production. Tomskneft VNK operates in the remote western part of the Tomsk Region in Western Siberia. Some of its more unusual assets include its own fleet of river barges and approximately 1,000 kilometers of service roads. Since over 70% of its recoverable reserves fall into the "difficult recovery" category, Tomskneft VNK has introduced advanced technologies for horizontal drilling and deep hydraulic fracturing of formations. It has also begun to acquire additional licenses for the development of several new areas in the Tomsk Region. At present there are 1880 production and 840 injection wells in operation. The average oil rate is 170 bbl/day, and the average water cut is 65%. OAO Yuganskneftegaz. OAO Yuganskneftegaz is the Yukos Oil Company's largest Production Association - and the second largest in all of Russia. Yuganskneftegaz, located in the Khanty-Mansi Autonomous Area of Western Siberia, first began operations in 1964, and has produced over 9 billion barrels of crude to date. At present, Yuganskneftegaz manages 29 fields, the largest of these being Priobskoye, Prirazlomnoye, Mamontovskoye, Malo-Balykskoye and Salymskoye. The Priobskoye field is unique as to its geological structure. Recoverable reserves are estimated at 3.01 billion barrels. Prirazlomnoye has 2 billion barrels reserves; a three-dimensional seismic survey of the field has revealed the existence of promising areas that could significantly increase production there. In order to improve well operation, Yuganskneftegaz is introducing hydraulic fracturing and implementing a program to increase efficiency and reliability at its production sites. The program includes improving the power supply system, purchasing additional up-to-date well equipment, and establishing a network of production supervisors. At present there are 6000 production and 2300 injection wells in operation. The average oil rate is 169 bbl/day, and the average water cut is 71%. OAO Tomskneft VNK. OAO Tomskneft VNK is the principal Production Association of Yukos subsidiary OAO "Vostochnaya nefteyanaya kompanya", also known as VNK or the Eastern Oil Company. Established in 1966, Tomskneft VNK has produced more than 2 billion barrels of oil since it began its operations. 21 fields are currently under development or in production. Tomskneft VNK operates in the remote western part of the Tomsk Region in Western Siberia. Some of its more unusual assets include its own fleet of river barges and approximately 1,000 kilometers of service roads. Since over 70% of its recoverable reserves fall into the "difficult recovery" category, Tomskneft VNK has introduced advanced technologies for horizontal drilling and deep hydraulic fracturing of formations. It has also begun to acquire additional licenses for the development of several new areas in the Tomsk Region. At present there are 1880 production and 840 injection wells in operation. The average oil rate is 170 bbl/day, and the average water cut is 65%. OAO Yuganskneftegaz. OAO Yuganskneftegaz is the Yukos Oil Company's largest Production Association - and the second largest in all of Russia. Yuganskneftegaz, located in the Khanty-Mansi Autonomous Area of Western Siberia, first began operations in 1964, and has produced over 9 billion barrels of crude to date. At present, Yuganskneftegaz manages 29 fields, the largest of these being Priobskoye, Prirazlomnoye, Mamontovskoye, Malo-Balykskoye and Salymskoye. The Priobskoye field is unique as to its geological structure. Recoverable reserves are estimated at 3.01 billion barrels. Prirazlomnoye has 2 billion barrels reserves; a three-dimensional seismic survey of the field has revealed the existence of promising areas that could significantly increase production there. In order to improve well operation, Yuganskneftegaz is introducing hydraulic fracturing and implementing a program to increase efficiency and reliability at its production sites. The program includes improving the power supply system, purchasing additional up-to-date well equipment, and establishing a network of production supervisors. At present there are 6000 production and 2300 injection wells in operation. The average oil rate is 169 bbl/day, and the average water cut is 71%.
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