Distillable Liquids Research Articles

Studies of Silylfurans, Furylsilanes, and Silylthiophenes: Structure of 2,5-Disilylthiophene

2-Silyl- and 2,5-disilylfuran (2-H3SiC4H3O, 2,5-(H3Si)2C4H2O) have been obtained from furan by lithiation with tBuLi, followed by treatment with H3SiBr at very low temperatures (−196 to −80 °C) in diethyl ether, as distillable liquids (bp 72 and 108 °C, respectively). Di-2-furyl- and tri-2-furylsilane ((2-C4H3O)nSiH4-n, n = 2, 3) are the products of the reaction of 2-furyllithium with Si(OMe)4, followed by reduction using LiAlH4 in diethyl ether/tetrahydrofuran. The methoxysilane precursors (2-C4H3O)nSi(OMe)4-n (n = 2, 3) have also been isolated. The analogous reactions of (MeO)4Si with equivalent quantities of (a) lithiated thiophenes and (b) LiAlH4 gave 2-silyl- and 2,5-disilylthiophene. Comprehensive NMR data have been compiled for all compounds, and the composition was confirmed by mass spectrometry. The crystal and molecular structure of 2,5-disilylthiophene has been determined by low-temperature “in situ” single-crystal X-ray diffraction, and ab initio calculations (MP2/6-31G*) have been carried out...

Trichlorosilylation of chlorogermanes and chlorostannanes with HSiCl 3/Net 3 followed by base-catalysed formation of (Me 3Ge) 2Si(SiCl 3) 2 and related branched stannylsilanes

Chlorotrimethylgermane 1 and dichlorodimethylgermane 4 react with trichlorosilane and triethylamine to provide trichlorosilylgermanes Me 4− n Ge(SiCl 3) n ( n=1: 2; n=2: 5) in fair yields, as distillable liquids. The formation of 2 is followed by base-catalysed decomposition reactions leading to novel solid (Me 3Ge) 2Si(SiCl 3) 2 3. Chlorotrialkylstannanes 6a– c ( 6a: R=CH 3, 6b: R=C 2H 5, 6c: R= n-C 4H 9) react with trichlorosilane and triethylamine providing the branched silylstannanes (R 3Sn) 2Si(SiCl 3) 2 7a– c and traces of silylstannanes R 3SnSiCl 3 8a– c. Only 7a was isolated in a pure state. Heating 7a or crude 7b and 7c with benzyl chloride leads to the formation of benzyltrichlorosilane ( 10). The constitution of compounds 2, 3, 5 and 7a was confirmed by MS, NMR and analytical data. The structures of C 6D 6-solvated 3 and C 6H 6-solvated 7a were determined by X-ray diffraction, and shown to be isotypic.

17.石炭液化油中のヘテロ化合物の構造・組成分析とその水素化反応性

17.石炭液化油中のヘテロ化合物の構造・組成分析とその水素化反応性

Modeling and Experimental Study of Operation Process in a Gas Turbine Combustor with a Plasma-chemical Element

The plasma-chemical technique for intensification of combustion is based on the interaction of a jet of low-temperature air plasma and the fuel. In order to determine the principal characteristics of a combustor operation process having a plasma-chemical element, an appropriate mathematical model has been used. Interphase interaction is taken into account by considering the drops of liquid as the sources of mass, impulse and heat for the gaseous phase. Simulation of plasma-chemical intensification processes is carried out through solving the equation of fuel concentration conservation in which the rate of its variation is expressed through the value of the resulting reaction of activation energy. Plasma-chemical action raises the efficiency of fuel combustion under idle running and partial loads conditions up to 3-9% as shown by experimental data obtained during the tests of a marine gas turbine combustor operating on distillate liquid fuel. The emission of carbon oxide during plasma-chemical reactor operation drops by a factor of 1.2- 1.6 depending on the amount of plasma-chemical products added.

An evaluation of motor function in transverse colon transplants after total gastrectomy.

The motor activity of the isolated colon is understood less than that of any other part of the gastrointestinal viscus. Thus, the aim of the present study was to evaluate the motor activity of the interposed transverse colon following total gastrectomy through a study of 21 patients. Manometric studies were carried out with a 5-lumen, open-tipped catheter in the resting state, in response to dry swallows, and swallowing distilled water and a liquid meal. Contractile waves in the interposed colon grafts were divided into three types, namely, high-amplitude propagated contractions (HAPCs), low-amplitude propagated contractions (LAPCs), and low-amplitude nonpropagated contractions (LANPCs). No retrograde contractions were observed during the entire recording. Motor activity in the interposed colon increased to a greater extent after swallowing distilled water or liquid meals than during the resting period or after dry swallows; however, there was no significant difference between the effect of distilled water and liquid meals. The motor activity of the interposed colon was lower in patients with symptoms than in asymptomatic patients. These results suggest that the volume, rather than the composition, of the lumen contents is an important factor for inducing interposed colon graft contractions, and that contractions of the interposed colon can help to propel the contents of the colon into the duodenum and clear any duodenal juice if reflux should occur.

Effect of phenolic resin on processing and mechanical properties of PP-NBR blends

Polymer mixtures based on polypropylene (PP) and acrylonitrile rubber (NBR) were prepared in a Haake Rheocord Mixer model 9000, coupled with a mixer chamber (cam rotors), in a proportion of 60:40/PP:NBR. These mixtures were processed in the presence either of phenolic resin SP-1045 or a phenolic derivative synthesized with cashew nut shell liquid (CNSL) distillate, in different concentrations. The influence of this component, as well as its concentration were evaluated by some processing data and through mechanical tests.

Bis(silylation) of Tris(dimethylamino)phosphonium Methylide

Abstract Treatment of (Me2N)3PCHSiMe3 with Me3SiOTf (OTf = triflate) affords the phosphonium salt [(Me2N)3PCH(SiMe3)2]OTf (2a), which can be converted into the correspond­ing ylide (Me2N)3PC(SiMe3)2 (3a) in high yield using NaN(SiMe3)2. The compounds with SiMe2Ph substituents (2, 3b) are obtained following an analogous procedure. The ylide (Me2N)3PC[Si(OMe)3]2 (3c) is available in 50% yield by direct transylidation of (MeO)3SiOTf with (Me2N)3PCH2 in the molar ratio 2:3, with [(Me2N)3PMe]OTf as the by-product. Com­pound 3c is a distillable liquid, but 3a,b are crystalline solids the structure of which has been determined by single crystal X-ray diffraction. Both compounds feature a trigonal planar ylidic carbon atom and short ylidic P-C and Si-C bonds. The nitrogen atoms are also in a planar configuration with non-standard orientations of the NMe2 groups at the phosphorus atoms. These data are in agreement with the results of recent quantum chemical calculations of simple prototypes which show very flat energy profiles for internal motions (rotation, inversion) of dimethylamino groups at the phosphorus atoms in phosphines and phosphoranes.

Introduction of Functional Silyl Groups into Tris(dialkylamino)phosphonium Methylides

Starting from tris(dialkylamino)phosphonium methylides(R2N)3PCH2 [1a: R = Me; 1b: R = Et] a series of silylated ylides with functional groups at the silicon substituents have been prepared (2 - 8 ). In the general formula X3Si-CH = P(NR2)3 the group SiX 3 represents examples for X = Me, Cl, Br, OMe, iPrO, NMe2, but also for X3 = PhH2 , etc. The compounds are prepared either via the transylidation reaction of 1a, b with reaction components X3SiY [Y = Cl, OTf], or through action of a base on the corresponding silylated phosphonium salts, following methods of preparation for non-functional silylated ylides. Bis(ylides) (9 - 12) are available along the same sequence of reactions, but employing difunctional silanes X2SiY2. Products of the type X2Si[CH = P(NR2)3]2 were investigated with X = Me, OMe, OEt, and NMe2. All ylides are thermally stable, distillable liquids, which have been identified via conventional spectroscopic methods. The ylides are versatile synthons in trans-silylation, trans-ylidation, and de-silylation reactions.

97/00999 Use of dispersed catalysts for direct coal liquefaction

With dwindling supplies of petroleum products, efforts to utilize alternative energy feedstocks such as coal, is essential. Several areas in coal conversion technology have been identified that, if improved, could make coal liquefaction more cost competitive with petroleum. The objectives of this project are to address possible improvements in the economics by utilizing low-rank coals, new precursors to dispersed catalysts, and processing variations such as using syngas atmospheres. The purpose of the dispersed catalysts is to better control retrogressive reactions and avoid char formation, while the purpose of the carbon monoxide atmosphere is to improve the economics by simplifying or totally eliminating a separate water-gas-shift step, and perhaps help remove oxygen in the product slate. These possible improvements are being examined and evaluated for potential use in a 2-stage liquefaction process with the goal of converting coal to distillable liquids at a cost competitive to petroleum of $25/bbl. To evaluate our catalysts and process conditions, we used three types of laboratory-scale operations. In the first operation, we compared the reaction chemistry of various ranks of coals and catalysts in synthetic solvents such as hexadecane. This method allowed us to better compare our catalysts without the complications of solvent initiated chemistry.more » Once the catalysts were tested in this manner, they were examined for the conversions of a Black Thunder subbituminous coal using a recycle vehicle derived from the same coal as the solvent. Finally, we upgraded selected first-stage conversion products using a conventional hydrotreating catalyst to compare with recent results in two-stage coal liquefaction development. The results were evaluated for economic feasibility through a subcontract with Bechtel Corp.« less

Relating Feedstock Composition to Product Slate and Composition in Catalytic Cracking. 2. Feedstocks Derived from Brass River, a High-Quality Nigerian Crude

The fluid catalytic cracking (FCC) behavior of compound types present in the >650 °F resid from Brass River (Nigerian) crude was investigated. Liquid chromatography and distillation were employed for separation of selected compound type fractions from the resid; the resulting fractions were then cracked using a bench scale FCC unit. The FCC behavior for each compound type was defined in terms of the resulting product distribution (yields of gas, gasoline, etc.) sulfur and nitrogen partitioning, and in selected cases, gasoline composition. Results obtained from Brass River fractions were compared to those obtained from an earlier FCC study of compound types from Wilmington, CA, >650 °F resid. Correlations were derived for gasoline and coke yields from feedstocks derived from either crude. Brass River is a sweet, paraffinic crude which gives rise to a >650 °F resid with very favorable FCC characteristics. Although the bulk of the FCC gasoline was produced from cracking hydrocarbon types present, significant...

Chemistry of Trichlorosilyl Enolates. 1. New Reagents for Catalytic, Asymmetric Aldol Additions

The asymmetric aldol addition is among the most powerful reactions in synthetic organic chemistry and has been extensively studied over the past 15 years.1 The strategies for reagentcontrolled asymmetric induction fall into three broadly defined classes (Chart 1): (1) asymmetric modification of the enolate with chiral acyl auxiliaries (A), (2) asymmetric modification of the enolate with chiral metalloid auxiliaries (B), and (3) asymmetric modification of the aldehyde with chiral Lewis acids (C). Each of these strategies has yielded spectacular success, and each has unique advantages and disadvantages. The chiral auxiliary approaches are extremely general and give high selectivities by virtue of the highly ordered nature of the transition structures (closed) which results from the structure of R*/L* and the organizational features of the metal M.1a,c,2 Unfortunately, these reactions have yet to be made catalytic. The chiral Lewis acid approach takes advantage of the Mukaiyama aldol reaction3 of enoxysilane derivatives and is demonstrably catalytic and often diastereoand enantioselective. However, these reactions are less general and the selectivity is most likely dominated by van der Waals interactions which guide the matching of enantiotopic faces in open transition states.3,4 We set for ourselves the goal of inventing a new type of aldol addition reaction which involves the ordered preassembly of enolate, aldehyde and chiral agent for maximum asymmetric influence and which would be catalytic in the chiral reagent. The formulation of this concept, Scheme 1, requires a metal enolate moiety capable of expanding its valence by two and a chiral Lewis base G*. The basis of this proposal for ligandpromoted aldehyde additions finds precedent in our recently disclosed asymmetric allylations (crotylations) with allylic trichlorosilanes.5 We wish to report that the corresponding trichlorosilyl enolates are highly reactiVe agents for the aldol reaction and that their additions can be asymmetrically catalyzed by chiral phosphoramides. While substantial literature exists on the generation and reactions of trichlorostannyl6 and trichlorotitanium7 enolates, the chemistry of trichlorosilyl enolates8 is embryonic by comparison.9 For the initial studies, the use of isolated, purified trichlorosilyl enolates was deemed essential, and we followed the general procedure of Baukov and Lutsenko,8a Scheme 2. Thus, from methyl tributylstannylacetate (1)10 we could obtain the trichlorosilyl ketene acetal 28a as a distillable liquid (bp 25 °C/5 mmHg),11 which thermally isomerized to methyl

The Separation of Deuterium and Tritium on PT/SDB/PS and PT/C/PTFE Hydrophobe Catalysts

The nature and performance of our patented catalysts, with platinum on carbon and polytetrafluorethylene [ Pt/C/PTFE ] and platinum on styrenedivynilbenzene and polystyrene [Pt/STB/PS], used in a water - hydrogen isotope exchange process are presented.The behaviour of the two catalysts in tritiated water was tested by determining their physical and structural characteristics as well as the catalytic activity before and after immersion in tritiated water.The test results emphasized that the two catalysts are highly active in the hydrogen - water vapor ( H2(g)-H2O(v) ) isotopic exchange and highly stable to tritium radiation.It was discovered that Pt/SDB/PS catalyst proved to be quite unstable in the hydrogen - water vapor - water (H2(g)-H2O(v)-H2O(1)) isotopic exchange, while the Pt/C/PTFE catalyst was highly stable. Thus, the Pt/C/PTFE catalyst was chosen for hydrogen isotope separation by liquid hydrogen cryogenic distillation combined with water - hydrogen isotopic exchange in a demonstration scale plant.

N-Nitroso-N-(n-butoxymethyl)arylamines

Abstract The title compounds were promptly obtained in fair to good yields as distillable liquids by admixing 1,3,5-triarylhexahydro-1,3,5-triazines (1) with n-butyl nitrite (2) in anhydrous CH2Cl2 and were fully characterized by 1H and 13C NMR, IR, and MS. The pure products were invariably made up of geometric isomers which did not interconvert rapidly at room temperature. o-Substituents could cause difficulties in the free rotations of the aryl substituent about the C–N bond as well of the α-butoxymethyl group. The reaction is believed to occur on the monomeric imines derived from the thermal equilibration of their trimeric and dimeric precursors. Aliphatic hexahydrotriazines were found to be unreactive under the present conditions.

Mass Transfer in Countercurrent Packed Columns: Application to Supercritical CO2 Extraction of Terpenes

Supercritical fluid extraction (SFE) is an alternative separation method to more conventional processes such as liquid extraction and distillation. However, up to now, few works have been devoted to the investigation of the efficiency of countercurrent packed columns under supercritical conditions from a mass transfer point of view. Mass transfer in a countercurrent column, filled with structured gauze packing, was measured for the separation of a mixture of terpenes (d-limonene/1,8-cineole) by supercritical carbon dioxide, at 313 and 318 K and pressures up to 9 MPa. The extraction efficiency was determined in terms of the overall mass transfer coefficient. Operating lines for this process had an appreciable curvature due to a high miscibility of the two contacting phases. The real slope of these lines had to be estimated. Available mass transfer models for packed columns predicted efficiencies diverging to a great extent from the experimental results.

Influence of Hydrogen and Catalyst on Distillate Yields and the Removal of Heteroatoms, Aromatics, and CCR during Cracking of Athabasca Bitumen Residuum over a Wide Range of Conversions

The percent conversion of sulfur, nitrogen, vanadium, nickel, aromatics, and CCR (Conradson carbon residue) has been analyzed as a function of residuum conversion for five series of reactions carried out in a batch reactor under nitrogen, hydrogen, or hydrogen in the presence of a residuum hydrotreating catalyst, over residuum conversions ranging from 38 to 86%. Sulfur, nitrogen, and CCR conversions could be divided into three categories, up to 50% residuum conversion, 50-70% residuum conversion, and greater than 70% residuum conversion. Sulfur conversion in the first category was from the distillable liquids and resulted from a combination of thermal, hydrogenation, and hydrogen atom addition reactions. Nitrogen removal in the first category was due to incorporation of nitrogen into reactor solids in the early stages of the reaction and was therefore suppressed by hydrogen in the absence of a catalyst.

Computer‐aided molecular design of solvents for separation processes

AbstractThe search for potential solvents for liquid extraction and extractive distillation is carried out through a group contribution molecular design of solvents (MOLDES) approach. A set of submolecular groups (UNIFAC) is used for the synthesis of molecular structures with desired solvent properties. Submolecular group combination (linking) properties are characterized to ensure the chemical feasibility of the MOLDES generated molecular structures. The size of the combinatorial problem posed by the molecular synthesis procedure is reduced by group selection and by imposing physical and molecular constraints at different stages. Criteria are developed for solvent evaluation and the reliability of the VLE and the LLE UNIFAC parameter tables for solvent screening are compared with experimental data for the recovery of oxychemicals by liquid extraction from dilute aqueous solutions.

The Pendant-Core Building Block Model of Petroleum Residua

Residua macromolecules can be approximated by various combinations of two building blocks that are linked by thermally labile bonds. The pendant building block is volatile when cracked off the rest of the residua molecule while the core building block remains nonvolatile. This simple model explains why the Conradson carbon residue, the standard measure of coking tendency, is a linear function of hydrogen content for petroleum molecules with molecular weights greater than 700 amu and why the cumulative properties of the distillable liquid products of the thermal conversion of residua are independent of conversion. In addition, the model provides a basis for calculating the change in the total Conradson carbon residue with processing of residua, including that it is unaltered by separation, decreased by hydroconversion and increased by thermal conversion.

Kidney cancer and hydrocarbon exposures among petroleum refinery workers.

To evaluate the hypothesis of increased kidney cancer risk after exposure to hydrocarbons, especially those present in gasoline, we conducted a case-control study in a cohort of approximately 100,000 male refinery workers from five petroleum companies. A review of 18,323 death certificates identified 102 kidney cancer cases, to each of whom four controls were matched by refinery location and decade of birth. Work histories, containing an average of 15.7 job assignments per subject, were found for 98% of the cases and 94% of the controls. To each job, industrial hygienists assigned semiquantitative ratings for the intensity and frequency of exposures to three hydrocarbon categories: nonaromatic liquid gasoline distillates, aromatic hydrocarbons, and the more volatile hydrocarbons. Ratings of "present" or "absent" were assigned for seven additional exposures: higher boiling hydrocarbons, polynuclear aromatic hydrocarbons, asbestos, chlorinated solvents, ionizing radiation, and lead. Each exposure had either no association or a weak association with kidney cancer. For the hydrocarbon category of principal a priori interest, the nonaromatic liquid gasoline distillates, the estimated relative risk (RR) for any exposure above refinery background was 1.0 (95% confidence interval [CI] 0.5-1.9). Analyses of cumulative exposures and of exposures in varying time periods before kidney cancer occurrence also produced null or near-null results. In an analysis of the longest job held by each subject (average duration 9.2 years or 40% of the refinery work history), three groups appeared to be at increased risk: laborers (RR = 1.9, 95% CI 1.0-3.9); workers in receipt, storage, and movements (RR = 2.5, 95% CI 0.9-6.6); and unit cleaners (RR = 2.3, 95% CI 0.5-9.9).

Separation and Concentration of Hydrogen Isotopes by a Palladium Alloy Membrane

A continuous membrane column process that uses a palladium alloy membrane for the separation of hydrogen isotopes is studied. Hydrogen, deuterium, and tritium permeation rates obtained in previous studies are used in numerical calculations in which the nature of the membrane column is investigated through variations in the operation variables, such as the pressures and their ratio, the reflux ratio, and the stripping column velocity. Finally, a cascade design in which membrane columns are used as unit cells is developed, following a design study of a nuclear fusion reactor fuel cycle system, and the concentrations and flow rates are calculated. The results show that hydrogen, deuterium, and tritium can be separated and concentrated as well by this method as by the liquid hydrogen distillation process. The inventory of the membrane column process is also calculated, and it is [approximately]2.3 times the fuel processed in a day.

Two different cyclization modes in the formation of silylhydrazines

The reactions of 1,2-bis(bromosilyl)ethane and 1,3-bis(bromosilyl)propane with anhydrous hydrazine lead to the two bicyclic silylhydrazines 1,6-diaza-2,5,7,10-tetrasila[4.4.0]bicyclodecane (1) and bis(1-aza-2,6-disila-1-cyclohexyl) (2), respectively. For compound 1, a distillable liquid with mp 7-degrees-C, the low-temperature crystal structure determination has shown a bicyclic configuration with the N-N unit shared by two slightly twisted, chair-formed heterocycles. The N-NSi2 Units are virtually planar but not orthogonal relative to each other owing to conformational restraints. In crystals of compound 2, mp 57-degrees-C, two six-membered rings each in a half-chair conformation are linked solely through the hydrazine N- N bond. The two planar NNSi2 units are at right angles as expected for a nonforced tetrasilylhydrazine geometry. The N-N bond is longer in 1 than in 2. Variable-temperature H-1 C-13 N-15, and Si-29 NMR spectra of both hydrazines have been measured, and the barrier of ring inversion of 1 has been determined.