Sasol (United Kingdom)

Summary Seismic amplitude evaluation in deepwater exploration is critical when assessing the prospectivity of an acreage. In Block ER236, offshore South Africa, interpretation of amplitude anomalies is challenged given the lack of well data preventing seismic calibration. Rock physics from the nearest wells and forward seismic modeling encouraged the use of elasto-mechanical attributes such as Compressibility and Shear Compliance. These properties maximise the discrimination of fluid and lithology effects, thus encouraging the implementation of the Wave-Equation Based AVO seismic inversion technique (WEB-AVO). The inverted Compressibility and Shear Compliance reveals a different character on the seismic anomalies compared to observations in stacks or weighted AVO attributes. On this light, Compressibility and Shear Compliance cross-plots have been useful to constrain the extent of the anomalies impacting on the uncertainty estimates and the overall understanding of the prospectivity in the area.

Although the first petroleum fields in the Mozambique basin were discovered more than 60 years ago, the composition and origin of petroleum fluids in this basin are largely unknown. We studied the geochemical composition of petroleum gases and liquids from the Inhassoro, Pande and Temane fields located onshore Mozambique. The gases are relatively dry (methane-dominated, average C1/(C1–C5) ratio is ~0.96), have pure thermogenic origin, originate predominantly from marine shale source organofacies and show no evidence of primary microbial gas or biodegradation. Most condensates have relatively high API gravity up to 76 degrees, are very mature and contain only traces of biomarkers, likely from migration contamination. However, biomarkers in the light oil from the Inhassoro field indicate that the oil derived from sub-oxic marine shales of the Late Cretaceous age. We suggest that the Aptian-Coniacian Domo Shale is the likely source rock for petroleum gases and liquids in the studied fields. Our geochemical data, including gas isotopes, as well as source-specific and age-specific biomarkers, exclude coals in the Late Carboniferous—Early Jurassic Karoo Supergroup as effective source rocks for the studied fields.

The facile insertion of CO2 into iridium(I) hydroxide, alkoxide, and amide bonds was recently reported. In particular, [Ir(cod)(IiPr)(OH)] (IiPr = 1,3-bis(isopropyl)imidazol-2-ylidene) reacted with CO2 in solution and in the solid state in a matter of minutes to give the novel [{Ir(cod)(IiPr)}2(μ-κ(1)O:κ(2)O,O-CO3)] complex. In the present study, this reaction is probed using kinetics and theoretical studies, which enabled us to analyse its facile nature and to fully elucidate the reaction mechanism with excellent correlation between the two methods.

The chromium(III) complexes of the type L1CrXY (L1 = 1-(2,6-diisopropylphenyl)-3-[β-(4,7-dimethylindenyl)ethyl]-imidazol-2-ylidene, X, Y = Cl, 2a-Cl; X = Cl, Y = Me, 2a-Me; X = Cl, Y = Ph, 2a-Ph; X, Y = benzyl, 2a-Bz) and L2CrCl2 (L2 = 1-(2,6-diisopropylphenyl)-3-[γ-(4,7-dimethylindenyl)propyl]-imidazol-2-ylidene, 2b-Cl) have been prepared and characterized by analytical and diffraction methods. The salts [L1CrCl(THF)]+[BArF4]− and [L2CrCl(THF)]+[BArF4]− (ArF = 3,5-bis(trifluoromethyl)phenyl) were also characterized, having been obtained by abstraction of chloride, or indirectly a methyl, from 2a-Cl or 2a-Me, and 2b-Cl, by NaBArF4, respectively. Reaction of 2a-Bz with 1 equiv of [H(Et2O)2][BArF4] in THF gave the thermally unstable salt [L1Cr(Bz)(THF)]+[BArF4], [2a-Bz]+[BArF4], which was also characterized crystallographically. The chromium(II) analogue L1CrCl, 3a, was prepared from CrCl2 and L1K, but on prolonged standing in THF, it converted to the dimeric complex 4a. The complexes 2a-Cl, 2b-Cl, 2b-Me, and 2a-Bz in the presence of an Al activator were tested as ethylene polymerization and oligomerization catalysts, in general, showing activity toward polymer formation.

A new family of N,N'-bis-(2,6-diisopropylphenyl)-(2,6-diisopropylphenyl-imidazolium)-acetamidines have been developed as NHC proligands and ligands that are functionalised with neutral amidine and anionic amidinato moieties. On coordination they adopt diverse binding modes, depending on the nature of the metal and the reaction conditions. In the Ag, K and Cr complexes reported in this paper, monodentate κ(1)(NHC), bimetallic bridging-(κ(1)-NHC-κ(1)-amidinato) and bidentate (κ(1)-NHC-κ(1)-amidinato) binding modes were observed, respectively. Two of the novel Cr complexes, in the presence of activators, were tested as catalysts for the polymerisation of ethylene showing low activity.

Keeping the organic and inorganic precursors in separate, immiscible solutions guides the growth of metal-organic frameworks into uniform thin layers that are shaped just like the liquid-liquid interface.

Ligand backbone alkylation of the complex [Cr(CO)4(dppm)] (dppm = bis(diphenylphosphino)methane) with alkyl iodides yields the C-substituted dppm ligand complexes [Cr(CO)4{Ph2PCH(R)PPh2}] (R = methyl, n-hexyl, benzyl). Activation of these complexes via one-electron oxidation with Ag[(Al(OC4F9)4] and CO removal with triethylaluminium, or (in the case of R = methyl) by in situ treatment of the free ligand with a chromium salt and modified methyl alumoxane (MMAO), leads to catalysts showing some selectivity for ethylene trimerization and tetramerization. NMR spectroscopic studies of the parent dppm or [Cr(CO)4(dppm)] compounds suggest that ligand deprotonation and decomplexation may be the cause of the surprisingly poor catalytic performance of these specific derivatives.

The syntheses of Co(eta3-C3H5)(CO)2PR2R' (R, R' = Ph, Me; R, R' = Me, Ph; R = R' = Ph, Cy, CH2Ph) and Co(eta3-C3H5)(CO)(L) (L = dmpe and dppe) are described, and X-ray structures for Co(eta3-C3H5)(CO)(dppe) and the PPh2Me, PCy3 derivatives reported. The relative ability of Co(eta3-C3H5)(CO)2(PR2R') to exchange phosphine for CO follows the trend PMe2Ph < PPh2Me < PCy3 < P(CH2Ph)3 < PPh3. Reactions of the allyl complexes with para-hydrogen (p-H2) lead to the observation of para-hydrogen induced polarisation (PHIP) in both liberated propene and propane. Reaction of these complexes with both CO and H2 leads to the detection of linear acyl containing species Co(COCH2CH2CH3)(CO)3(PR2R') and branched acyl complexes Co(COCH(CH3)2)(CO)3(PR2R') via the PHIP effect. In the case of PPh2Me, additional signals for Co(COCH2CH2CH3)(CO)2(PPh2Me)(propene) and Co(COCH(CH3)2)(CO)2(PPh2Me)(propene) are also detected. When the reactions of H2 and diphenylacetylene are studied with the same precursor, Co(CO)3(PPh2Me)(CHPhCH2Ph) is seen. Studies on how the appearance and ratio, of the PHIP enhanced signals vary as a function of reaction temperature and H2 : CO ratio are reported. These profiles are used to learn about the mechanism of catalysis and reveal how the rates of key steps leading to linear and branched hydroformylation products vary with the phosphine. These data also reveal that the PMe2Ph and PPh2Me based systems yield the highest selectivity for linear hydroformylation products.

China now holds the world's largest foreign exchange reserves mainly thanks to dynamic export activities. In order to invest and manage these foreign exchange reserves, the Chinese government recently announced the constitution of a new State Foreign Exchange Investment Company (SFEIC) aimed at improving the yield on them. This new investment vehicle will face multiple challenges ranging from showing solid financial gains to establishing effective rules for corporate governance that guarantee transparency in company management. In addition to the legal aspects, numerous economic and political implications will arise from this new government-controlled tool.

Dimethylindenyl-functionalized N-heterocyclic carbene complexes of titanium(IV), titanium(III), zirconium(IV), and vanadium(III) were prepared from potassium indenylcarbenes by salt elimination reactions. X-ray diffraction studies revealed that in the complexes the ligand adopts a bidentate coordination mode. Alkanolysis of a dimethylindene-functionalized imidazolium salt with Y(CH2SiMe3)3(THF)2 gave rise to a dimeric yttrium bromo alkyl in which the ligand adopts a bidentate coodination mode. Aminolysis of the fluorene-functionalized imidazolium salts with {[Cr(N(SiMe3)2)2(THF)2} led to chromium(II) complexes in which the ligand adopts a monodentate binding mode via the N-heterocyclic carbene end with dangling fluorene groups.