Disposal of drilling waste in salt mines in China.

A lot of drilling wastes are produced during oil/gas exploration and exploitation in China. Many countries have built and successfully run projects to dispose of wastes in salt mines, which fully demonstrates the feasibility and superiority of this technology. The application prospects of using salt mines to dispose of drilling wastes is comprehensively evaluated from many aspects.

Chiral surfactant-type catalyst: enantioselective reduction of long-chain aliphatic ketoesters in water.

A series of amphiphilic ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neat water. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and ε-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst 2.

The research on borehole stability in depleted reservoir and caprock: using the geophysics logging data.

Long-term oil and gas exploitation in reservoir will lead to pore pressure depletion. The pore pressure depletion will result in changes of horizontal in-situ stresses both in reservoirs and caprock formations. Using the geophysics logging data, the magnitude and orientation changes of horizontal stresses in caprock and reservoir are studied.

The self-assembly of cystine-bridged γ-peptide-based cyclic peptide-dendron hybrids.

Novel cystine-bridged γ-peptide-based cyclic peptide-dendron hybrids have been synthesized by oxidative coupling between two cysteine residues of the linear peptides via the formation of disulfide bonds in high yields. The self-assembly of the hybrids was studied by FT-IR, (1)H NMR, TEM, and AFM analyses which indicate that the nanotube was constructed through intermolecular hydrogen-bonding of the hydrophobic cyclic peptide moieties and possesses amphiphilic property by conjugating a hydrophilic dendron on the exterior of the cyclic peptide ring. The diameters of nanofibers that consisted of nanotubes depend on the employed solvent in the self-assembly process, and uniform filaments formed from double amphiphilic nanotubes via hydrophobic interactions between their hydrophobic faces have been observed in water as well as in aqueous solutions.

An asymmetric normal-electron-demand aza-Diels-Alder reaction via trienamine catalysis.

An asymmetric normal-electron-demand aza-Diels-Alder cycloaddition of 2-aryl-3H-indol-3-ones and 2,4-dienals was explored via trienamine catalysis of a chiral secondary amine. Multifunctional tricyclic polyhydropyrido[1,2-a]indoles were efficiently constructed in good stereoselectivity (up to 92% ee, >19 : 1 dr).

An asymmetric allylic alkylation-Smiles rearrangement-sulfinate addition sequence to construct chiral cyclic sulfones.

An asymmetric allylic alkylation of Morita-Baylis-Hillman carbonates and β-keto sulfones was investigated by the catalysis of modified cinchona alkaloids, whose products underwent a Smiles rearrangement-sulfinate addition cascade to furnish highly functionalized five-membered cyclic sulfones in moderate to excellent enantioselectivity and good diastereoselectivity after treatment with DBU.

Wellbore stability in oil and gas drilling with chemical-mechanical coupling.

Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced.

Chiral surfactant-type catalyst for asymmetric reduction of aliphatic ketones in water.

A novel chiral surfactant-type catalyst is developed. Micelles formed in water by association of the catalysts themselves, and this was confirmed by TEM analyses. Asymmetric transfer hydrogenation of aliphatic ketones catalyzed by the chiral metallomicellar catalyst gave good to excellent conversions and remarkable stereoselectivities (up to 95% ee).

Preparation and helical folding of aromatic polyamides.

Long aromatic polyamide chains are prepared from the corresponding monomers. The resultant polymer adopts a hollow helical conformation that is stabilized by intramolecular H-bonding interaction between side chains.

Covalent reinforcement of hydrogen-bonded discs into stably folded helical structures.

The presence of covalent tethers significantly enhanced the stability of structures consisting of helically arranged benzenetricarboxamide units that otherwise undergo very weak hydrogen-bonding interaction. The resultant molecular structures were probed by computational study, which predicted folded conformations consisting of helically arranged discs. Experimental studies confirmed the H-bonding interaction between the disk units, the monomeric nature of the corresponding molecules in solution, and the helical conformations of such molecules.

Multiresponsive chiroptical switch of an azobenzene-containing lipid: solvent, temperature, and photoregulated supramolecular chirality.

An azobenzene-containing lipid was designed as a functional organogelator, and its self-assembly as well as the chiroptical properties were investigated. The gelator shows good gelation ability in various organic solvents ranging from polar to nonpolar solvents. Although the molecule did not show a CD signal in the absorption band of azobenzene in solution, supramolecular chirality was observed upon gel formation.

Chemoselective conjugate reduction of alpha,beta-unsaturated ketones catalyzed by rhodium amido complexes in aqueous media.

Although a notable feature of Noyori's Ru-TsDPEN complex is that the transfer hydrogenation reaction is highly chemoselective for the C=O functional group and tolerant of alkenes, our early report indicated that the chemoselectivity could be switched from C=O to C=C bonds in the transfer hydrogenation of activated alpha,beta-unsaturated ketones. Now we have found that a variety of alpha,beta-unsaturated ketones, even without other electron-withdrawing functional groups, could be reduced on the alkenic double bonds with high selectivities employing amido-rhodium hydride complex in aqueous media, and up to 100% chemoselectivity has been achieved. It is notable that the chemoselectivity was improved significantly on going from organic solvent to water.

A C(2)-symmetric chiral bis-sulfoxide ligand in a rhodium-catalyzed reaction: asymmetric 1,4-addition of sodium tetraarylborates to chromenones.

A new C(2)-symmetric chiral bis-sulfoxide ligand, (R,R)-1,2-bis(tert-butylsulfinyl)benzene, has been designed and prepared by the reaction of (R)-benzyl tert-butylsulfoxide with (R)-thiosulfinate. This ligand exhibits excellent enantioselectivities in the Rh-catalyzed asymmetric 1,4-addition reaction. In particular, the present work has realized access to optically pure flavanones for the first time through 1,4-addition of arylboronic reagents to chromenones.

Aryl tert-butyl sulfoxide-promoted highly enantioselective addition of allyltrichlorosilane to aldehydes.

A series of enantiomerically pure mono- and bis-aryl tert-butyl sulfoxides were synthesised to promote the enantioselective allylation of aldehydes with allyltrichlorosilane. Moderate to good yields and modest to high enantioselectivities were achieved. The absence of nonlinear effect, spacer effect, promoter loading and concentration effect indicate that only one molecule of aryl tert-butyl sulfoxide is involved in the stereodetermining step.

Crescent oligoamides as hosts: conformation-dependent binding specificity.

Crescent oligoamides have been found to bind substituted guanidinium ions with high specificity and affinity.

Aggregation and columnar assembly of crescent oligoamides.

The aggregation and assembly of crescent oligoamides with two to six benzene residues are investigated. In chloroform, the pentamer and hexamer are found to associate into large aggregates. In the solid state, all oligomers examined associate into columnar assemblies via stacking interactions, as shown by X-ray diffraction data from single crystals and powder samples.

Membranes and membrane processes for chiral resolution.

This critical review is devoted to an active field of research on chiral separation, membrane-based enantioseparation technique, which has potential for large-scale production of single-enantiomer compounds. Adsorption-type enantioselective membranes and membrane-assisted resolution systems with non-enantioselective solid membranes have attracted much attention recently. The principles and recent developments of both enantioselective liquid and solid membranes and membrane-assisted processes for chiral resolution will be summarized comprehensively in this review, in which the contents are of interest to a wide range of readers in a variety of fields from analytical, organic and medicinal chemistry, to pharmaceutics and materials, to process engineering for fabricating pharmaceuticals, agrochemicals, fragrances and foods, and so on (148 references).

Highly enantioselective Michael addition of malononitrile to alpha,beta-unsaturated ketones.

The highly enantioselective Michael addition of malononitrile to acyclic and cyclic alpha,beta-unsaturated ketones has been developed. The Michael reaction catalyzed by a primary amine derived from quinidine proceeded smoothly and provided the desired adducts with excellent enantioselectivities (83-97% ee).

Efficient method for the synthesis of polysubstituted benzenes by one-pot tandem reaction of vinyl malononitriles with nitroolefins.

The one-pot synthesis of polysubstituted benzene derivatives was achieved via vinylogous Michael addition of vinyl malononitriles and nitroolefins as the key step and a sequential tandem reaction. A series of complex aryl compounds such as biphenyls and terphenyls can be obtained with satisfactory yields.

Highly enantioselective michael addition of cyclic 1,3-dicarbonyl compounds to alpha,beta-unsaturated ketones.

[reaction: see text] The highly enantioselective Michael addition of 1,3-cyclic dicarbonyl compounds to alpha,beta-unsaturated ketones was reported to be catalyzed by an organic primary amine derived from quinine. A chiral anticoagulant drug, (S)-warfarin, was directly prepared in 96% ee, and other related important adducts were also obtained in excellent enantioselectivity (89-99% ee).

Asymmetric transfer hydrogenation catalysed by hydrophobic dendritic DACH-rhodium complex in water.

Hydrophobic Fréchet-type dendritic chiral 1,2-diaminocyclohexane-Rh(III) complexes have been applied in the asymmetric transfer hydrogenation of ketones in water using HCOONa as hydrogen source. The catalysts were found to be finely dissolved in the liquid substrates in the aqueous mixture and exhibited high catalytic activity and enantioselectivity (52-97% ee). The catalytic loading could be decreased to 0.