SiC>2 as silica gel, fused silica, or quartzite will react readily in ethylene glycol (EG) with 1 equiv of alkali (M) hydroxide (except Na) to produce, in essentially quantitative yield, monomeric pentacoordinate glycolato silicates [M(0CH2CH20)2Si0CH2CH20H] containing two bidentate glycol ligands and one monodentate ligand. On heating, one EG is lost per two monomer units forming dimeric species, [M2Si2(0CH2CH20)s], or polymers, C^OksL-The Na derivative precipitates out of solution as the dimer. In experiments run with fused silica, the dissolution process exhibits a first-order dependence on base concentration and silica surface area. The Ea for silica dissolution is 14 ± 2 kcal/mol with AH* % 11 kcal/mol and AS* % -44 cal/mol K. In the absence of base, the silica surface reacts with EG to form an alkoxy-modified surface as determined by diffuse reflectance FTIR spectroscopy (DRIFTS). In the presence of base, only hydroxyl groups are seen on the silica surface. A mechanism for dissolution is proposed based on these observations. The dissolution process appears to be relevant to the nonaqueous synthesis of zeolites, especially silica-sodalite (ZSM-5), which are prepared under very similar conditions. The monomeric, anionic glycolato silicates exhibit trigonal-bipyramidal geometry, with no apparent contact interactions between the anionic framework and the alkali metal counterions. The monomers, dimers and polymers are characterized by chemical analysis, X-ray powder diffractometry, FTIR, solution and solid-state MAS 29Si NMR, and thermal gravimetric analysis. The monomers dissolve readily in methanol but appear to do so via a ligandexchange process wherein some of the glycolato ligands are displaced by methoxy ligands. On heating, the dimers/polymers decompose to phase-pure alkali silicates.

Most shale reservoirs (e.g., Bakken Shale and Eagle Ford) have a low permeability, low porosity, and oil-wet character with natural fractures. As a result, the oil recovery factors are very low, only a few percent of original oil in place. Injection of water into oil-wet reservoirs (i.e., water flooding) is not effective due to small or negative capillary pressure. In this study, various surfactants (non-ionic, cationic, anionic, and amphoteric) were studied for spontaneous imbibition into oil-wet shale cores. Surfactant imbibition into Eagle Ford shale outcrop cores and Bakken reservoir cores increased oil recovery compared to brine only. Oil recovery can be seen for surfactants that alter the reservoir from oil-wet to water-wet. For example, the incremental oil recovery was about 24% % for 0.1% cationic surfactant and 57% for 0.1% nonionic surfactant. The goal of this work is to investigate the effect of salinity, surfactant concentration, electrolyte concentration, and temperature on the wettability alteration and provide mechanisms. Contact angles and interfacial tensions (IFT) were measured and correlated with spontaneous imbibition. Wettability alteration from oil-wet to water-wet (i.e., low contact angle) appeared to be more important than a low interfacial tension in increasing the oil recovery rate from fractured oil-wet reservoirs, especially for nonionic surfactants and amphoteric surfactants. Wettability alteration is maximum and IFT is minimum for anionic and cationic surfactants at an optimal salinity. However, as the reservoir salinity increases, the maximum wettability alteration decreases and IFT increases.

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(&, = 0.032); equivalent reflections were merged. The structure was solved by a combination of Patterson and difference Fourier techniques. The final cycle of full-matrix least-squares refinement was based on 5784 observed reflections ( I > 3.00a (I)) and 326 variable parameters and converged (largest parameter shift was less than 0.009 times its esd) with R = 0.060 and R , = 0.063. A final difference Fourier map showed no chemically significant features. Crystal data are a = 13.084(2), b = 13.089(2), c =13.194(2) Carbon dioxide insertion into the metal-oxygen bond of metal hydroxides, alkoxides, and aryloxides is a fundamental step in several chemical and biochemical catalytic processes. Notable among these processes are the coupling of CO, and epoxides to provide cyclic carbonates ['] or polymeric materials,"] and the hydration of CO, to afford carbonic acid.[31 Attendant with reactions involving low-valent anionic Group 6 metal alkoxy-or aryloxycarbonyl complexes is the lability of the carbonyl ligands which can subsequently lead to P-hydrogen elimination or metal aggregation reaction^.'^' In this communication, we report the synthesis and structural characterization of carbonyl catecholatotungsten complexes and the effect of the n-donating property of these dihydroxo ligands on the reactivity patterns of the metal complexes.A solution of [W(CO),thf] (prepared photochemically from 1.9 mmol of [W(CO),] in tetrahydrofuran) was transferred to a Schlenk flask containing 3.8 mmol of (Et,N)(OC,H,OH) and stirred. An orange powder precipitated within one hour and orange crystals of 1 were isolated by filtration (1.3 g or 90 % yield) and recrystallization from CH,CN/ether. The infrared spectrum of 1 in CH,CN exhibited vco vibrations at 1975(w), 1829(vs), 1807(m, sh) and 1773(m) cm-'. Two sharp doublets of equal intensity were observed for the CO ligands in the 13C NMR spectrum at 6 = 217.6 (Jw,c =I65 Hz) and 207.5 =131 Hz).Definitive assignment of the structure of 1 was obtained by X-ray crystallography; the result is shown in Figure 1 .151 The solid-state structure of 1 is characterized by continuous hydrogen bonding between the bridging catechol moiety and two adjacent dianions. The structure shows typical hydro- The complex 2 containing only coordinated catechol was obtained by reacting 1.6 mmol of 1 with three equivalents of NaOMe in acetonitrile. Na,0,C,H4 and excess NaOMe were removed by filtration through Celite, and dark orange crystals (yield 0.91 g, 82 %) were obtained upon addition of THF/Et,O to the filtrate. As anticipated, the vco vibrations of 2 in CH, CN (1965(w), 1817(vs), 1800(m,sh) and 1763(m) cm-') are shifted to lower frequencies than those of 1, indicative of' some hydrogen bonding of 1 in solution as well. Similarly the two 13C NMR resonances in CH,CN shift downfield to 6 = 219.6 (Jw.c = 159 Hz) and 208.8 ( J . , = 133 Hz). More importantly, in contrast to species 1, the carbonyl ligands in the non-hydrogen-bonded form of the complex are fluxional. Coalescence of the two carbonyl carbon signal...