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Titanocene complexes [Ti(η 5 -C 5 H 5− n Me n ) 2 (η 2 -Me 3 SiCCSiMe 3 )] ( n =0, 4 and 5) react uniformly with siladiynes R 2 2 Si(CCR 1 ) 2 , where R 1 =Ph, and R 2 =Ph or Me, at elevated temperature in hydrocarbon solvents to give the corresponding silacyclobutene-annelated titanacyclobutene complexes, 3-bis(η 5 -cyclopentadienyl)titana-6-diorganylsilabicyclo[2.2.0]hexa-1(2),4(5)-dienes, [(η 5 -C 5 H 5− n Me n ) 2 Ti{R 1 2 C 4 (SiR 2 2 )}]. Products arising from [Ti(η 5 -C 5 H 5− n Me n ) 2 (η 2 -Me 3 SiCCSiMe 3 )] ( n =0, 2 (1,3-isomer), 4 and 5) and Me 2 Si(CCCMe 3 ) 2 vary with n : the non-methylated titanocene complex affords a mixture of an analogous silacyclobutene-annelated titanacyclobutene and [{Ti(η 5 -C 5 H 5 ) 2 } 2 {μ-η(3–5):η(4–6)-Me 3 CCCCCCMe 3 }], the permethylated titanocene precursor gives mainly the allyldiene complex [Ti(η 5 -C 5 Me 5 )(η 3 :η 4 -C 5 Me 3 (CH 2 ) 2 )] while no titanium-containing product could be isolated for n= 4. The reaction of [Ti(η 5 -1,3-C 5 H 3 Me 2 ) 2 (η 2 -Me 3 SiCCSiMe 3 )] with Me 2 Si(CCCMe 3 ) 2 , however, cleanly affords the expected silacyclobutene–titanacyclobutene complex. All complexes were studied by spectral methods and solid-state structure of two representatives, [(η 5 -C 5 Me 5 ) 2 Ti{Ph 2 C 4 (SiMe 2 )}] and [(η 5 -1,3-C 5 H 3 Me 2 ) 2 Ti{(Me 3 C) 2 C 4 (SiMe 2 )}] was determined by single-crystal X-ray diffraction.

The synthesis and characterization of a series of titanium dichloride derivatives containing both cyclopentadienyl and various substituted aryloxide ligands, [CpTi(OAr)Cl2] 10−18 and [Cp*Ti(OAr)Cl2] 19, 20, have been investigated. Compounds 10−18 are formed from the reaction of [CpTiCl3] with either 1 equiv of the substituted parent phenol in the presence of excess pyridine or with 1 equiv of the corresponding lithium salt of the substituted parent phenoxide in hydrocarbon solvents. Compounds 13, 14, 16, and 17 are chiral molecules (a nonresolved racemic pair) as a result of the presence of either ortho-(1-naphthyl) or ortho-(1-tetrahydronaphthyl) substituents on the phenoxide ligands. Titanium dichloride compounds 19 and 20 are formed in the reaction of [Cp*TiCl3] with the corresponding lithium salts of the substituted parent phenoxides in hydrocarbon solvents. The compounds 11, 13, 14, 15, 16, 18, 19, and 20 have been subjected to single-crystal X-ray diffraction analysis, and each was shown to possess ...

The initial rates of air oxidation of eight aromatic phosphites were measured at 200°C in hydrocarbon solvents. The phosphites were oxidized to the corresponding phosphates, and, in every case, a small amount of the corresponding substituted phenol was also detected. The phenolic compounds likely arose from hydrolysis of the phosphites by water generated during oxidation. In general, alkyl substitution caused a decrease in the rate of oxidation. Phosphite 7 [bis(2,4-dicumylphenyl) pentaerythritol diphosphite] and, to a lesser extent, phosphite 6 [bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite] had a combination of high rate of oxidation and good resistance towards hydrolysis in the bulk state, a combination that is not usual with most commercially available phosphites (1).

In an LCA case study, the three most frequent industrial metal cleaning technologies were assessed: Cleaning based on aqueous cleaning agents, non-halogenated hydrocarbon solvents and halogenated hydrocarbon solvents. Beside optimisation analysis, the comparison of the cleaning processes was a main goal of the study. The function of metal cleaning processes can be described with a set of parameters called functional parameters. In order to compare different cleaning processes within LCA, it is a precondition that all relevant functional parameters be equivalent. However, metal cleaning processes from different companies normally differ in most of the functional parameters and, thus, are not functionally equivalent. Therefore, it is necessary to calculate the material and energy flows of the processes corresponding to a reference function as a basis for comparison. This can be achieved by simulating the processes according to the functional parameters with the help of a process model. For a general comparison of the technologies, it is also necessary to consider the assessed machines having the same level of optimisation and the same scale.

α-Lithioalkoxysilanes, [(RO)R 2 ′Si]CH(Li)(R″) (R=Me, Et; R′=Me, Ph; R″=H, SiMe 3 ), can be prepared by treating the appropriate alkoxysilane with tert -butyllithium in hydrocarbon solvents. For R=Me or Et, R′=Me, and R″=H or SiMe 3 , the α-lithioalkoxysilanes are produced in high yield. Similar treatment of alkoxysilane 12 , EtOPh 2 SiCH 3 , afforded the corresponding α-lithioalkoxysilane 13 (R=Et, R′=Ph and R″=H), in moderate yield, along with substitution product 14 , tert- BuPh 2 SiCH 3 . Analogous reactions with n -butyl- and sec -butyllithium in hydrocarbon solvent produced significant or exclusive substitution at silicon, rather than α-lithiation.

The role played by surfactant molecular architecture in determining its effectiveness as a dispersant for carbonaceous solid substrates in hydrocarbon solvents is investigated using simple analytic theory and adsorption experiments carried out with model and commercial succinimides on activated carbon. We show by both of these approaches that the length and backbone structure of the hydrophobic tail are significant factors in determining the efficiency of the adsorption process and therefore probably the dispersancy mechanism itself. All of the succinimides are shown to be ‘high affinity’ adsorbates.

The reaction of [Cp*TaCl4] with the potassium salt of carbazole (cbK, >3 equiv) in hydrocarbon solvents leads to the species [(C5Me4CH2)Ta(cb)2Cl] (1), in which one of the ring methyl C−H bonds of ...

We have explored the use of hydroperoxide decomposing species for inhibiting oxidation in jet fuel. We find that hydroperoxide decomposing species, such as alkyl sulfides, do not slow or delay oxidation in hydrocarbon solvents at 140 °C. However, when phenolic species are also present, such as those naturally occurring in fuel or by addition of hindered phenols, substantial delays in oxidation are observed. We used a pseudo-detailed chemical kinetic mechanism to provide insight into the oxidation process. The combination of hydroperoxide decomposer and hindered phenol can substantially inhibit oxidation of fuel under the conditions studied here.

Lipophilic deoxyguanosine 1 in pure hydrocarbons or in mixed CHCl3-hydrocarbon solvents forms a new lyotropic liquid crystalline phase characterized by a two dimensional square packing. The structural elements of the phase are ribbon-like assembled species which are completely different from the columnar structures, based on G-quartets, which are the building blocks of the mesophases formed by deoxyguanosine oligonucleotides in water.

We report the first example of acceleration of a bimolecular reaction by increased solvent viscosity. In a series of hydrocarbon solvents of graded viscosity, the rates of two cycloadditions, the Diels−Alder dimerization of cyclopentadiene and the 1,3-dipolar cycloaddition of diphenyldiazomethane with ethyl phenylpropiolate, rise with increasing viscosity to about 1 cP and then fall thereafter. We interpret this rise as viscosity-induced acceleration up to ∼1 cP, which cannot be accounted for by current kinetic theory. Several examples from the literature are reinterpreted in these terms, providing further support for our concept.

Solvent-borne formulations are a mature segment of the paints market, but a resilient one. They retain a high degree of consumer acceptance, due to their performance, application and appearance characteristics, combined with their cost-effectiveness. The solvent is a lower value constituent of the formulation, but use of higher quality alternatives has been limited.

The reaction of Ph3Bi with ButOOH in a mole ratio of 1: 3 in hydrocarbon solvents affords the η2-peroxo complex of triphenylbismuth Ph3Bi(η2O2) which oxidizes the C-H bonds of the methylene group of dibenzyl sulfide. The reaction proceeds via the radical mechanism with the formation of intermediate unstable sulfur-containing hydroperoxide. Its decomposition is accompanied by the C-S bond cleavage, resulting in benzaldehyde.

Trialkyl phosphates OP(OR)3 (R = Me, Et, Ph, SiMe3) react with AlMe3, AlEt3, and GaMe3 in hydrocarbon solvents to form the adducts Me3Al.OP(OR)3 (R = Me (1), Et (2), Ph (3), SiMe3 (4)), Et3Al.OP(OR)3 (R = SiMe3 (5)), and Me3Ga.OP(OR)3 (R = Me (6), SiMe3 (7)). These products were characterized by 1H, 13C, 29Si, and 31P NMR, infrared (IR), and mass (MS) spectroscopies, and elemental analysis. The trimethylsilyl ester adducts 4, 5, and 7 further undergo a thermally induced dealkylsilylation with the formation of cyclic alumino- and gallophosphate dimers, [R'2M(m2-O)2P(OSiMe3)2]2 (R'2M = Me2Al (8), Et2Al (9), and Me2Ga (10)). The molecular structures of 8 and 9 were confirmed by X-ray crystallography.

A new and inexpensive technique to obtain vertical hydrochemical profiles in aquifers is presented. The Dual Pumping Technique (DPT) is designed for use in fully-screened groundwater wells and represents an alternative to packer installations or similar sampling devices. Two pumps are placed at either end of the well screen. The ratio of their pumping rates is varied from 1 to 0. Depending on this ratio, the two pumps abstract variable portions of the influx distribution. A water divide develops in the well, separating the flow upward from the flow downward. A set of samples from the upper and lower pump are taken for different pumping rate ratios. Measured solute concentrations in these samples, together with the influx distribution determined by flow logging, are used to reconstruct vertical concentration profiles. The measured data are evaluated with a simple, robust algorithm, which is derived in the text and exemplified in the Appendix. The DPT was used to determine vertical concentration distributions of chlorinated hydrocarbon solvents (CHS) and tritium in a contaminated aquifer near Heidelberg, Germany. Comparison of the concentration profile obtained with the DPT with CHS and tritium data from a 50-m distant multilevel well showed the principal applicability of the new technique. The pattern of the vertical concentration distributions was successfully identified with the DPT, but the absolute CHS concentration values were one order of magnitude higher in the multilevel well, due to the fact that the multilevel well is probably closer to the centre of the plume than the well used for the DPT. The 3H values could be compared directly and showed an excellent agreement. Further evaluation of the DPT in a situation where a multilevel reference well is in closer vicinity to the test well is planned.

New single-source precursor to tantalum nitride thin films, (But N)Ta(NEt2)3, and relate complexes, (RN)Ta(NEt2)3 (R = Pri and Prn), were prepared by reacting corresponding (RN)TaCl3py2 complexes (R = But, Pri and Prn) with LiNEt2 in hydrocarbon solvents. The structure of (ButN)TaCl3py2 was determined by X-ray crystallography.

A survey of solvent was conducted for 196 unit work areas in 95 plants in 1994 to 1996 in Hiroshima Prefecture, Japan. The survey had been repeated every 6 months (i.e., twice a year) during the 3-year period. Sampling and analysis of the solvent vapors were carried out after national protocols set by the regulation. Toluene was most frequently detected regardless of the type of solvent work (except for degreasing), whereas the second- and the third-most common solvents varied depending on the type of solvent works. Among chlorinated hydrocarbon solvents for degreasing, dichloromethane was most widely used. Solvent concentrations were generally low as none of the median concentrations exceeded corresponding Administrative Control Levels set by the regulation, either individually or even when the assumption of additiveness was applied. Among the 1176 cases analyzed, 80% of the unit work areas were evaluated as adequate (i.e., classified as Class I). Furthermore, about 57% stayed in Class I throughout the 3 years, suggesting that solvent exposure conditions were generally quite stable. In regulatory evaluation by classification, A-sampling was decisive in most cases, whereas the role of B-sampling was limited.

A sensitive comparative fluorescence microscopic approach was developed and used to study the water at the air-water interface region. An insoluble chromophore mesoc-α,β,γ,δ-tetraphenylporphine (TPP) was spread on the water. Its fluorescence spectrum indicated that the spectrum of TPP on the water surface was similar to those measured in nonpolar hydrocarbon solvents. Thus, the water at the surface was concluded to be hydrophobic and less polar than the water in the bulk.

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 97854, "Experimental Observations of Miscible Displacement of Heavy Oils With Hydrocarbon Solvents," by D. Salama and A. Kantzas, U. of Calgary, prepared for the 2005 SPE International Thermal Operations and Heavy Oil Symposium, Calgary, 1–3 November. The increased interest in secondary production (or post-cold production) of heavy oil and the rise of oil prices have renewed interest in solvent-based methods for heavy-oil recovery. Although the vapor-extraction (vapex) process is favored, other methods are worth investigating. Also, the relative merit of mass-transfer and viscous mechanisms in the overall recovery efficiency remains a topic of debate. This study of mass-transfer phenomena in heavy-oil/ and bitumen/solvent systems was performed in an effort to determine dispersion coefficients. Introduction Heavy oil and oil sands will be an important part of Canada's oil supply. One-third of the world's oil is in Canada in the form of heavy oil and bitumen. The world's heavy-oil resources total approximately 10 trillion bbl, nearly three times the conventional oil in place in the world. Alberta contains nearly 2 trillion bbl of oil. Approximately one-fourth of the oil production of Canada is from oil sands. Here, in-situ recovery processes are thermal or nonthermal. Thermal processes use heat to reduce the viscosity of the heavy oil in situ, thus mobilizing the heavy oil. Examples include cyclic-steam stimulation, steam-assisted gravity drainage, and steamflooding. Nonthermal processes rely on dilution of the oil to reduce the heavy-oil viscosity. Examples include CO2 injection, miscible floods, and vapex. Displacement in the case of immiscible floods, such as waterflooding, generally is not complete, but a fluid can be displaced completely from the pores by a miscible fluid. In the case of miscible fluids, there are no residual saturations. Hence, sol-vent floods present an attractive in-situ process for the recovery of the heavy oil. However, the major challenge in miscible floods is for the miscible phase to access a significant fraction of the resident oil. In solvent-based enhanced-oil-recovery techniques, several mechanisms affect the rate of oil recovery, given that accessibility is provided. These mechanisms include mass transfer, viscous forces, and gravity drainage. The solvent diffuses and/or disperses into the heavy oil, reducing its viscosity. The solvent/oil mixture then drains and is recovered from the production well. This study focused on the mass-transfer process in miscible sol-vent floods by experimentally observing the miscible displacement of heavy oils by hydrocarbon solvents.

The presence of halogen atoms in elastomeric macromolecules lends them some very advantageous properties, such as chemical resistance, flame retardancy, and less swelling in hydrocarbon solvents and oils. Thermosetting elastomers containing halogens have been used commercially for decades. However, halogen-containing thermoplastic elastomers are relatively new, and some of them are currently still in development; this chapter discusses these new and upcoming products.

Reaction of the triphenylphosphine chalcogenides Ph3PE (EO, S, Se) with PhCH2Mn(CO)5 at 70–90°C in hydrocarbon solvents gave the orthomanganated derivatives (OC)4MnC6H4P(E)Ph2 in 41% (EO), 90% (ES) or 22% (ES) yields. The different yields are rationalised in terms of the preferred angles of coordination at the E atom and the PE bond stability. The new compounds were fully characterised, including X-ray crystal structure determinations for the examples with ES and Se. (OC)4MnC6H4P(S)Ph2 reacted with P(OMe)3 to replace two of the CO ligands without disrupting the MnS bond; an X-ray structure determination shows the two phosphite ligands are trans to each other, and have little effect on the geometry of the rest of the molecule.

The huge natural resources present in the form of heavy oil and bitumen may be the principal source of fuel for human civilization in the coming century. However, due to very high viscosities of these crudes the use of conventional recovery techniques is not feasible. The viscosity decreases drastically with increase in temperature; this principle is utilized in thermal recovery processes like SAGD. Using long horizontal wells, very high production rates can be achieved in this process. However, steam processes suffer from energy inefficiency largely due to heat losses to the cap and base rock. This can be avoided if instead of steam, solvent is used to reduce viscosity. In the proposed process, “Vapex”, vaporized hydrocarbon solvents are used to extract heavy oil and bitumen using the concept of gravity drainage. Hydrocarbon solvents, when present in sufficient concentration, causes deasphalting of these crudes. Although deasphalting improves the quality of the produced crude, the possibility of...

Four new triply-bonded ditungsten complexes of the formula cis,cis-W2Cl4(NHCMe3)2(L-L) (L-L = dmpm (1), dmpe (2), dppm (3), dppe (4)) have been prepared by reaction of W2Cl4(NHCMe3)2(NH2CMe3)2 with the appropriate bidentate phosphines (L-L) in hydrocarbon solvents. These complexes are the first triply-bonded complexes of the form W2Cl4(NHR)2(L-L) where L-L groups are bidentate phosphines. The molecular structures have been investigated by X-ray crystallography. Crystal data are as follows: for 1, monoclinic space group P21/n, a = 13.807(1) A, b = 11.835(2) A, c = 15.348(1) A, β = 109.19(2)°, Z = 4; for 2, P21/n, a = 14.144(2) A, b = 11.991(1) A, c = 15.662(2) A, β = 109.50(1)°, Z = 4; for 3·CH2Cl2, P21/c, a = 18.777(6) A, b = 10.273(2) A, c = 21.082(3) A, β = 94.11(6)°, Z = 4; for 4, P21/n, a = 11.938(1) A, b = 18.583(3) A, c = 17.606(2) A, β = 106.54(6)°, Z = 4. The W−W bond lengths for 1, 2, 3·CH2Cl2, and 4 are 2.3247(4), 2.3274(5), 2.328(1), and 2.3452(5) A, respectively, which are consistent with a f...

Polyynes solutions having as main components C6H2 and C8H2 can be prepared in hydrocarbon solvents by hydrolyzing calcium carbide in an NH4Cl aqueous solution containing Cu(I)/Cu(II) salts. The polyynes are released into a hydrocarbon solvent by acidification with concd. HCl. Heptane solutions with polyynes concentration as high as 0.1 M can be easily prepared.

The present analyses were initiated to elucidate changes in types of prevalently used organic solvents in various solvent workplaces in Japan during the past 30 years. Five publications on industrial solvent use were employed as databases, which were supplemented by solvent workplace surveys in 2010–2012; the surveys were conducted following regulation-stipulated procedures. In practice, data on 500–600 unit workplaces/year were available; the data were classified by types of solvent work according to the regulation. The use of aromatic solvents (typically toluene) has been gradually replaced in a recent few years with methyl alcohol and isopropyl alcohol in surface coating workplaces, whereas toluene has been essentially most prevalent in printing and painting workplaces. In cleaning workplaces, the use of chlorinated hydrocarbon solvents was almost terminated in the years before 2000. The present study may be the first report to note that the prevalence of toluene use has been decreasing in surface coating workplaces to be replaced by alcohols, although toluene has been most prevalent in printing and painting workplaces. In cleaning workplaces, there was a substantial reduction in the use of chlorinated hydrocarbon solvents.

In the modern era as the demand of energy is increasing and conventional resources are limited, every Nation and Industry is focusing towards exploitation of Unconventional resources t fulfill the future needs. With the application of VAPEX in offshore and thin reservoir we will be able to recover heavy oil. The recovery of heavy oil present series of challenges like its high viscosity which creates problem in production & transportation, sulphur & nitrogen content, high content of heavy metals etc. Many thermal and non-thermal methods are used for the recovery of Heavy Oil. Out of the thermal methods VAPEX and SAGD are important one. Nowadays VAPEX is given preference over SAGD as it minimize the environmental and economical risk. Vapex involves injection of vaporized hydrocarbon solvents into heavy oil reservoir; the diluted oil drains by gravity to a horizontal production well.Different Solvents which can be used with their benefits in Vapex process is studied in detail. The author has explained the process of VAPEX and SAGD in detail with the advantages of VAPEX over SAGD.

The results described herein demonstrate the advantages of functionalized initiators with respect to the efficiency of α-chain-end functionalization and the ability to effect post-polymerization functionalization and linking reactions with the living ω-carbanionic chain ends. Not all functionalized initiators are useful, however, because either: (a) they are not soluble in hydrocarbon solvents; or (b) they are not reactive enough to initiate polymerization at rates which are competitive with propagation to prepare polymers with narrow molecular weight distributions and controlled molecular weights; or (c) they are either too difficult to prepare or too expensive to prepare to be readily available for commercial elastomer production. The advantages of using funcitonalized initiators, however, should encourage further scientific and technological developments in this area.

The problem of assigning Occupational Exposure Limits (OELs) to complex hydrocarbon solvents has been with the industry for many years. In the mid 1970s Carpenter et al. (1975, 1976a,b, 1977, 1978) undertook a programme of work for the American Petroleum Institute (API) in which the toxicology of a number of hydrocarbon fractions was investigated. Sixteen hydrocarbon solvents were studied and hygienic levels were proposed (Table 1). At about the same time the Hydrocarbons Solvents Association (now the Solvents Industry Association) employed the ACGIH Reciprocal Calculation Procedure (RCP), using the limited available data, to calculate OELs for the major hydrocarbon solvents. On reviewing the approaches made more recently by France, Germany, the U.K., Denmark, Norway and Sweden when dealing with the problem of mixed solvents, the RCP, in one form or another, has been frequently employed (Table 2).

The photolysis of low molecular weight ketones (4-tridecanone, 3- and 5-dodecanone) at wavelengths longer than 300 nm and in hydrocarbon solvents has been investigated by FTIR, GC/MS and GC/FTIR. The quantum yield and the rate of decomposition were compared with those of a low molecular weight hydroperoxide (3-hydroperoxyhexane).

Although toxic chemical ocular exposures are common, there has been little epidemiologic study of this problem. We carried out a systematic follow-up study of symptomatic ocular exposures reported to a regional poison control center (PCC). We interviewed 279 (76%) of 368 patients reported to the PCC that met study criteria. Exposures were heterogeneous, including personal care and medicinal products, 42 (15%); hydrocarbon solvents 30 (11%); hypochlorite bleach, 20 (7%); strong acids and bases 19 (7%); and all other causes 168 (60%). The median duration that eye irrigation was performed as a first aid measure was 15 min; 203 (73%) initiated irrigation within 2 min or less. Only 30 (11%) reported that symptoms persisted longer than 2 days; 85 (31%) were treated by a physician for the exposure. Taking into account other factors such as type of exposure and extent of involvement, reported increased length of irrigation time was associated with worse outcome whether measured by number of symptoms (odds...

[108915-07-7] C12H16N2O (MW 204.27) InChI = 1S/C12H16N2O/c1-9(2)7-10-8-15-12(14-10)11-5-3-4-6-13-11/h3-6,9-10H,7-8H2,1-2H3/t10-/m0/s1 InChIKey = MFEIEQDUFOSLGN-JTQLQIEISA-N (chiral ligand for enantiocontrol of metal-catalyzed reactions) Physical Data: [α]20D −93.4 (c 20.0, PhMe), bp 160–170 °C/ 0.1 Torr. Solubility: soluble in aromatic (PhH, PhMe) and chlorinated hydrocarbon solvents. Form Supplied in: oil. Preparative Methods: reaction of pyridine carboximidate with (S)-leucinol in MeOH at 60 °C generates (S)-(−)-4-(2-methylpropyl)-2-(2-pyridyl)-2-oxazoline in 68% yield (eq 1).1 Reaction of (S)-leucinol with 2-picolinic acid (2-pyridinecarboxylic acid) in the presence of an excess of PPh3, iPr2EtN, and CCl4 (slow addition) in CH2Cl2 yields, after 24 h, (S)-(−)-4-(2-methylpropyl)-2-(2-pyridyl)-2-oxazoline in 68% yield (eq 2).2, 3 (1) (2) Purification: can be purified by Kugelrohr distillation. Handling, Storage, and Precautions: stable at ambient temperature.

Among various aluminosilicate supports, the K10 montmorillonite clay was the best catalyst for the oxidation of organic substrates with potassium ferrate (VI) Thus, a solid mixture of K 2 FeO 4 and K10 has been used for the efficient oxidation of selected alcohols, benzylamine, thiophenol. and aniline in hydrocarbon solvents at room temperature. Somewhat humid clay performs best, and it is important to control the amount of water associated to the solid support.

Several substituted β-tetralols 1a–c and β-tetralol 2 were successfully resolved using porcine pancreatin in hydrocarbon solvents. All attempts to resolve the substituted β-tetralols by diasteromeric derivatization have failed. The absolute configuration of the products was established by literature precedence.

Hexane has been used for decades to extract oil from cottonseed and is still the solvent of choice for the edible-oil industry. Due to increased regulations as a result of the 1990 Clean Air Act and potential health risks, the edible-oil extraction industry urgently needs an alternate hydrocarbon solvent to replace hexane. Based on laboratory-scale extraction tests, two hydrocarbon solvents, heptane and isohexane, were recommended as potential replacements for hexane. A cottonseed processing mill with a 270 MT/day (300 tons/day) capacity agreed to test both solvents with their expander-solvent process. Extraction efficiencies of isohexane and heptane, judged by extraction time and residual oil in meal, refined and bleached color of miscella refined oil, and solvent loss, were comparable to that of hexane. However, fewer problems were encountered with the lower-boiling isohexane than with the higher-boiling heptane. With isohexane, the daily throughput increased more than 20%, and natural gas consumption decreased more than 40% as compared to hexane.

Nd, La and Y triphosphates were prepared via the reaction of potassium ionol ethyl phosphate with the corresponding lanthanide nitrates or chlorides in water. According to the X-ray diffraction data, the recrystallised reaction products were dimers. The products did not contain water, were readily soluble in hydrocarbon solvents and demonstrated promising catalytic properties in the polymerisation of butadiene and DL-dilactide.

Certain o- and m-disubstituted aromatics where both substituents are directing metallation groups (DMG's) should, in contrast to singly substituted DMG-containing arenes, undergo metallation in hydrocarbon solvents. It is proposed that the activation of such systems towards ortho-metallation is a synergistic generation of the appropriate bis-chelated alkyllithium dimer structure as well as complexed stabilization of the transition state.

A series of complexes (η 5 -C 5 H 5 )Fe(CO) 2 Si 2 Me 4 Ar, FpSi 2 Me 4 Ar (Ar= C 6 H 4 ; X=H, p-Cl, m-CF 3 , o-Me, p-OMe, p-NMe 2 ), have been synthesized and characterized. Photochemical treatment of the complexes in inert hydrocarbon solvents led to expulsion of the SiMe 2 and/or SiMeAr fragments to yield FpSiMe 3 and /or FpSiMe 2 Ar

Metal bis(dicarbollides) of the type M(B[sub 9]C[sub 2]H[sub 11])[sub 2][sup [minus]] (M = Co, Fe) have been incorporated into cationic organothorium complexes [Cp[prime][sub 2]ThR][sup +]X[sup [minus]] (Cp[prime] = [eta][sup 5]-(CH[sub 3])[sub 5]C[sub 5]; R = alkyl, H) as potential weakly coordinating anions. The reaction of Cp[prime][sub 2]Th(CH[sub 3])[sub 2] with [HNEt[sub 3]][sup +]Co(B[sub 9]C[sub 2]H[sub 11])[sub 2][sup [minus]] and [HNEt[sub 3]][sup +] [Fe(B[sub 9]C[sub 2]H[sub 11])[sub 2]][sup [minus]] in hydrocarbon solvents affords [Cp[prime][sub 2]ThCH[sub 3]][sup +] Co(B[sub 9]C[sub 3]H[sub 11])[sub 2][sup [minus]] and [Cp[prime][sub 2]ThCH[sub 3]][sub 2][sup 2+] [Fe(B[sub 9]C[sub 2]H[sub 11])[sub 2]][sup 2[minus]] (2), respectively. The structure of 2 reveals tight ion-pairing with three close Th-H-B bridging interactions (2.42(3), 2.50(3), 2.67-(4) A). This level of Th coordinative saturation explains the unexpected chemical inertness of 1 and 2. The reaction of Cp[prime][sub 2]Th[CH[sub 2]Si(CH[sub 3])[sub 3]][sub 2] with [HNEt[sub 3]][sup +]Co(B[sub 9]C[sub 2]H[sub 11])[sub 2][sup [minus]] affords [Cp[prime][sub 2]ThCH[sub 2]Si(CH[sub 3])[sub 3]][sup +] [Co(B[sub 9]C[sub 2]H[sub 11])[sub 2]][sup [minus]] (3), which slowly undergoes hydrogenolysis to yield [Cp[prime][sub 2]ThH][sup +] [Co(B[sub 9]C[sub 2]H[sub 11])[sub 2]][sup [minus]] (4). 18 refs., 2 figs., 3 tabs.

The design of absorption processes and gas liquid reactors requires the knowledge of gas solubility data. It is shown that a modified UNIFAC-FV model can be applied to predict Henry's constants for hydrocarbon gases and vapors in high-boiling hydrocarbon solvents. Very good agreement with experimental data has been achieved.

Groundwater quality in the Coventry aquifer system was surveyed using the 42 accessible boreholes. Pollution by chlorinated hydrocarbon solvents (CHSs) is widespread in the urban area, with trichloroethene being the major pollutant. CHS pollution is closely associated with industrial land use, except for trichloromethane which appears to be linked to leakage of chlorinated water from water mains and sewers. Modelling studies suggest that most of the urban groundwater is already polluted by dissolved CHSs, and that natural flushing of the aquifer will take hundreds of years. Inorganic pollution has also occurred in the urban area, and is linked mainly to leakage from sewers, in contrast to most CHS pollution. Little, if any, degradation of CHSs is taking place in the aquifer, and pollution continues; the poor quality of Coventry groundwater will, therefore, persist for the foreseeable future.

The broader implications of the Coventry Groundwater Investigation are discussed in this postscript. The complex interbedded sandstone and mudstone sequence under Coventry is seriously polluted by chlorinated hydrocarbon solvents. Investigations in such terrain will require much greater expenditure than was available for this project if they are to describe the distribution and movement of pollutants in enough detail to evaluate, quantitatively, options for aquifer clean-up. It is not realistic to consider clean-up of Coventry's groundwater at the present time because of the lack of detailed knowledge. It is probable, at least for the present, that clean-up is not feasible, because of hydrogeological constraints arising from the extreme variability of permeability in the system and an absence of operational techniques for clean-up. Stronger, more pro-active protection of groundwater is needed. A major recommendation for future investigations is a procedure to avoid open boreholes, which can allow pollution to penetrate deeper into the aquifer, and may confuse the results of sampling.

The thermal reactions of Ru3(CO)12 with RCOCH=CHPh (R=Me, p-MeC6H4) in hydrocarbon solvents lead to the formation of a series of complexes, several of which have been isolated as individual compounds by chromatography. The dinuclear complex Ru2(μ-H)(CO)6(μ-MeCOCH=CPh) and the tetranuclear complex Ru4(μ-H)(μ-CO)(CO)7(p-MeC6H4 COCH=CPh)(μ-p-MeC6H4COCH=CPh)(μ4-p-MeC6H3COCH=CHPh) are characterized by an X-ray structural study. The structures of other reaction products are discussed on the basis of spectral data. The reactions are accompanied by reduction of the starting enones to the corresponding unsaturated ketones.

Chlorinated hydrocarbon solvents are often used for dry-cleaning clothes in the laun- dry industry. The object of this study was to monitor the occupational exposure of dry-clean employees coming into contact with VOXs. Twenty five workers collected their urine samples before the work shift, after 4 h of work and after the work shift. The analyses of urine sam- ples and solvents used in dry-cleaning were performed using TLHS-DAI-GC-ECD. Chloroform was detected in all urine samples, and dichloromethane and tetrachloroethene in nearly all urine samples collected before and after the work shift. The concentrations of the compounds determined in urine samples were higher at the end of the workday in directly exposed indi- viduals. Concentrations of the compounds determined in urine samples depended mainly on the type of activities carried out at the dry-cleaning establishments.

The reaction of the anhydrides of boronic or borinic acids with trihaloboranes in hydrocarbon solvents leads to the clean exchange of the oxygen and halide to form the organodihaloboranes and diorganohaloboranes in good to excellent yields.

Several substituted β-tetralols 1a–c and β-tetralol 2 were successfully resolved using porcine pancreatin in hydrocarbon solvents. All attempts to resolve the substituted β-tetralols by diasteromeric derivatization have failed. The absolute configuration of the products was established by literature precedence.

Alkynyldichlorogalliums dimerize in hydrocarbon solvents via carbogallation giving 1,1-dimetallo-1-buten-3-yne derivatives.

Making use of the fact that perfluorohydrocarbon, and hydrocarbon solvents become miscible at high temperatures, highly pure inorganic nanoparticles capped with fluorous labels have been generated in a one-step synthesis. The procedure involves taking the reactants in a hydrocarbon+perfluorohydrocarbon mixture along with a fluorous reagent and carrying out the reaction at elevated temperatures. On cooling the reaction mixture, fluorous-capped inorganic nanoparticles dispersed in the perfluorohydrocarbon are obtained.

The lipophilic 3′,5′-di-O-decanoyl-2′-deoxyguanosine (1) in CHCl3 undergoes extensive self-assembly, mediated by H-bonding between the guanine bases, to give ribbon-like aggregates. X-Ray investigation of the platelets obtained from CHCl3 reveals a disordered fibre-like structure consisting of stacks of the ribbon-like aggregates. The aggregates are completely different from the columnar structures, based on G-quartets, which are the building blocks of the mesophases formed by deoxyguanosine oligonucleotides in H2O. In pure hydrocarbons or in CHCl3/hydrocarbons, 1 forms a lyotropic liquid-crystalline phase.

Some methyl 4,6-O-benzylidene monosaccharides can act as strong low molecular weight gelators for various organic solvents. As they are accessible in a variety of homologues, each with a unique molecular architecture, they can be used for systematic studies of gelation phenomena. Structural details of their hydrogen-bond-based fiber network in the gel phase can be resolved by small angle X-ray scattering (SAXS). Analysis of the molecular arrangement in a single crystal can be a valuable tool for the prediction of gelation ability presupposing that the elongated shape of the gel fibers arises from an anisotropic assembly of the gelator molecules into one-dimensional aggregates. It is found that some derivatives act as “supergelators”, which can gelate hydrocarbon solvents with 0.03–0.05 wt %. The recent results emerging from these investigations will be outlined in this article.