Addition Of CH3OH Research Articles

Peroxidase-like biomimetic epoxidation and subsequent alcoholysis of olefins by Fe(III)tetrakis(4-sulphonatophenyl) porphyrin (Fe4SP) encapsulated in the metal-organic framework HKUST-1

The efficiency and diverse functionality of biological catalysts has inspired the synthetic design of systems to mimic the stabilizing and catalytic properties of enzyme substrate binding protein pockets. One such system is the Fe4SP@HKUST-1 metal organic framework (MOF) system, also known as MOMzyme-1, in which Fe(III)tetrakis(4-sulphonatophenyl)porphyrin (Fe4SP) is encapsulated within the cuboctahedral cavities of the HKUST-1 MOF. Within this system the Fe4SP heme active site is encapsulated in a pseudo protein pocket within the MOF. Here, the ability of the Fe4SP@HKUST-1 to catalyze the tandem epoxidation of olefins followed by selective alcoholysis is examined. It is observed that encapsulation of Fe4SP within the MOF framework significantly enhances the turnover number (TON) of peroxide-driven epoxidation of styrene while greatly reducing metalloporphyrin degradation and maintaining stereoisomer selectivity. The Fe4SP@HKUST-1 catalyzes both the olefin epoxidation and the subsequent ring opening through the addition of CH3OH. The epoxidation of styrene occurs through the hydrogen peroxide generated high valent Fe(IV) = O of the encapsulated Fe4SP while the corresponding ring opening and methanolysis takes place at the Cu metallo building blocks of the HKUST-1 framework. These results provide a framework through which to develop a more extensive library of bio-inspired heme-based MOF catalysts.

Photosynthesis of Au/TiO2 nanoparticles for photocatalytic gold recovery from industrial gold-cyanide plating wastewater

A series of Aux/TiO2 nanoparticles (NPs) with different gold loadings (x = 0.1–1.0 wt%) was synthesized by the photodeposition and then employed as photocatalysts to recover precious component from the industrial gold-cyanide plating wastewater. Effects of Au loading, catalyst dosage and types of hole scavenger on the photocatalytic gold recovery were investigated under ultraviolet–visible (UV–Vis) light irradiation at room temperature. It was found that different Au loadings tuned the light absorption capacity of the synthesized photocatalysts and enhanced the photocatalytic activity in comparison with the bare TiO2 NPs. The addition of CH3OH, C2H5OH, C3H8O, and Na2S2O3 as a hole scavenger significantly promoted the photocatalytic activity of the gold recovery, while the H2O2 did not. Among different hole scavengers employed in this work, the CH3OH exhibited the highest capability to promote the photocatalytic gold recovery. In summary, the Au0.5/TiO2 NPs exhibited the best photocatalytic activity to completely recover gold ions within 30 min at the catalyst dosage of 0.5 g/L, light intensity of 3.20 mW/cm2 in the presence of 20 vol% CH3OH as hole scavenger. The photocatalytic activity slightly decreased after the 5th cycle of recovery process, indicating its high reusability.

Effect of impurities on glycerol steam reforming over Ni-promoted metallurgical waste driven catalyst

This study investigates the effect of common impurities (methanol (CH3OH), acetic acid (CH3COOH), and oleic acid (C18H34O2)) containing in crude glycerol on the efficiency of a residue-driven catalyst (Ni/UGSO) for H2 production through glycerol steam reforming under different operation conditions (temperature between 580 and 730 °C, steam to carbon molar ratio (S/C) of 3 and 6). The presence of CH3OH increases H2 yield (YH2) from 76.9% to 81.7% while CH3COOH and C18H34O2 (i) decrease both YH2 (to 73.5% and 56.8%, respectively) and conversion of carbon to gaseous products (from 99% to 96.4% and 80.2%, respectively) and (ii) enhance coke formation. Stable performance during 30 h was achieved in the presence of CH3OH followed by CH3COOH and C18H34O2 with a slight deactivation only (YH2= 79%, 65.1%, and 55.5%, respectively). Addition of CH3OH and CH3COOH leads to more graphitic-typed coke formation, while a less structured coke was observed in case of C18H34O2.

Shape-Persistent Oxa- and Aza-calix[4]arene Hybrid Molecular Cage and Naked Eye Sensing of Fluoride.

An oxa- and aza-calix[4]arene hybrid molecular cage with a large, shape-persistent cavity wrapped by aromatic rings was designed and synthesized via multifold efficient SNAr reactions. X-ray single-crystal analysis revealed that two THF molecules were encapsulated in the central cavity. Selective sensing of F- in apolar solvent leads to naked eye discriminable color change. Addition of CH3OH would recover the color of the molecular cage.

Comparative study of the hydrogen bonding properties between bis(fluorosulfonyl)imide/bis(trifluoromethyl)sulfonylimide-based ether-functionalized ionic liquids and methanol

Bis(fluorosulfonyl)imide ([FSI]−) and bis(trifluoromethyl)sulfonylimide ([TFSI]−)-based ionic liquids have potential applications in electrochemistry. However, some fundamental questions regarding their hydrogen bonding properties remain to be answered. In this work, the hydrogen bonding interactions between two [FSI]− and [TFSI]−-based ionic liquids and methanol (CH3OH) and their microscopic structure were comparatively investigated by infrared spectroscopy, excess spectroscopy and quantum chemical calculations. Some conclusions can be drawn: (1) The hydrogen bonding interactions in the two systems are strengthened with the addition of CH3OH. Moreover, EOMIMFSI ([EOMIM]+, 1-methoxyethyl-3-methylimidazolium) can form stronger hydrogen bonds with CH3OH than EOMIMTFSI. (2) The excess peaks of v(O–H), v(aromatic C–Hs) and vas(S=O) show fixed positive and negative excess peaks, indicating distinct complexes. With combination of the excess spectra and quantum chemical calculations, the newly formed distinct complexes were assigned to the ion cluster-CH3OH, the ion pair-CH3OH, and isolated ion-CH3OH complexes. The microscopic structure of the two systems was also shown with dilution. (3) The C4–H in EOMIMFSI is the main interaction site interacting with CH3OH, while the C2–H in EOMIMTFSI is the main interaction site.

Stereoselectivity of Additions toN-Methyl Acetonitrilium Fluorosulfonate

Alkoxy-N-methyl-acetiminium salts were prepared by addition of CH3OH and C2H5OH to N-methyl acetonitrilium fluorosulfonate at low temperature. Analysis of the 5J(HH) and 3J(13C–H) coupling constants in the NMR spectra showed an anti addition with a diastereoselectivity of >95%. Deprotonation of these salts with (Z)-configuration gave the corresponding N-methyl-alkoxyacetimines with very high (E)-configuration. Upon protonation at −78 °C, these iminoesters gave the corresponding alkoxy-N-methyl-acetiminium salts with (E)-configuration. Computational analyses of the iminoesters and the corresponding iminium cations including the conformations give insight into the relative stability. Nitrilium salts can be used as reagents, exemplified by some esterifications between simple acids and alcohols.

Mechanistic Features of Isomerizing Alkoxycarbonylation of Methyl Oleate

The weakly coordinated triflate complex [(P^P)Pd(OTf)](+)(OTf)(-) (1) (P^P = 1,3-bis(di-tert-butylphosphino)propane) is a suitable reactive precursor for mechanistic studies of the isomerizing alkoxcarbonylation of methyl oleate. Addition of CH(3)OH or CD(3)OD to 1 forms the hydride species [(P^P)PdH(CH(3)OH)](+)(OTf)(-) (2-CH(3)OH) or the deuteride [(P^P)PdD(CD(3)OD)](+)(OTf)(-) (2(D)-CD(3)OD), respectively. Further reaction with pyridine cleanly affords the stable and isolable hydride [(P^P)PdH(pyridine)](+)(OTf)(-) (2-pyr). This complex yields the hydride fragment free of methanol by abstraction of pyridine with BF(3)·OEt(2), and thus provides an entry to mechanistic observations including intermediates reactive toward methanol. Exposure of methyl oleate (100 equiv) to 2(D)-CD(3)OD resulted in rapid isomerization to the thermodynamic isomer distribution, 94.3% of internal olefins, 5.5% of α,β-unsaturated ester and <0.2% of terminal olefin. Reaction of 2-pyr/BF(3)·OEt(2) with a stoichiometric amount of 1-(13)C-labeled 1-octene at -80 °C yields a 50:50 mixture of the linear alkyls [(P^P)Pd(13)CH(2)(CH(2))(6)CH(3)](+) and [(P^P)PdCH(2)(CH(2))(6)(13)CH(3)](+) (4a and 4b). Further reaction with (13)CO yields the linear acyls [(P^P)Pd(13)C(═O)(12/13)CH(2)(CH(2))(6)(12/13)CH(3)(L)](+) (5-L; L = solvent or (13)CO). Reaction of 2-pyr/BF(3)·OEt(2) with a stoichiometric amount of methyl oleate at -80 °C also resulted in fast isomerization to form a linear alkyl species [(P^P)PdCH(2)(CH(2))(16)C(═O)OCH(3)](+) (6) and a branched alkyl stabilized by coordination of the ester carbonyl group as a four membered chelate [(P^P)PdCH{(CH(2))(15)CH(3)}C(═O)OCH(3)](+) (7). Addition of carbon monoxide (2.5 equiv) at -80 °C resulted in insertion to form the linear acyl carbonyl [(P^P)PdC(═O)(CH(2))(17)C(═O)OCH(3)(CO)](+) (8-CO) and the five-membered chelate [(P^P)PdC(═O)CH{(CH(2))(15)CH(3)}C(═O)OCH(3)](+) (9). Exposure of 8-CO and 9 to (13)CO at -50 °C results in gradual incorporation of the (13)C label. Reversibility of 7 + CO ⇄ 9 is also evidenced by ΔG = -2.9 kcal mol(-1) and ΔG(‡) = 12.5 kcal mol(-1) from DFT studies. Addition of methanol at -80 °C results in methanolysis of 8-L (L = solvent) to form the linear diester, 1,19-dimethylnonadecandioate, whereas 9 does not react and no branched diester is observed. DFT yields a barrier for methanolysis of ΔG(‡) = 29.7 kcal mol(-1) for the linear (8) vs ΔG(‡) = 37.7 kcal mol(-1) for the branched species (9).

Regeneration of a Compost Biofilter Degrading High Loads of Ammonia by Addition of Gaseous Methanol

The long-term stability of a biofilter loaded with waste gases containing NH3 concentrations larger than 100 ppmv was studied in a laboratory-scale compost reactor. At an empty bed residence time (τ) of 21 sec, elimination capacities of more than 300 g NH3/m3/day were obtained at elimination efficiencies up to 87%. Because of absorption and nitrification, almost 80% of the NH3-N eliminated from the waste gas could be recovered in the compost as NH4+-N or NO2 −/NO3 −-N. The high elimination capacities could be maintained as long as the NH4+/NOx concentration in the carrier material was less than 4 g NH4+/NOx −-N/kg wet compost. Above this critical value, osmotic effects inhibited the nitrifying activity, and the elimination capacity for NH3 decreased. To restore the biofilter performance, a carbon source (methanol) was added to reduce NH4+/NOx − accumulated in the compost. Results indicate that methylotrophic microorganisms did convert NH4+/NOx − into biomass, as long as the NO3 − content in the compost was larger than 0.1 g NO3 −-N/kg compost. Removal efficiencies of CH3OH of more than 90% were obtained at volumetric loads up to 11,000 g CH3OH/m3/day. It is shown that addition of CH3OH is a suitable technique for regenerating the compost material from osmotic inhibition as a result of high NH3 loading. The biofilter was operated for 4 months with alternating loading of NH3 and CH3OH.

Optically Active Transition Metal Complexes, XXXIV (+)579‐ and (‐)579‐(‐C5H5)Mo(CO) (NO)[P(C6H5)2N(CH3)CH(CH3)(C6H5)

AbstractIn the reaction of C5H5Mo(CO)2NO +) with (+)579 n‐(C6H5)2PN(CH3)CH(CH3) (C6H5), abbreviated with PØ2R*, the pair of diastereoisomers (+)579‐ and (‐)579‐ C5H5Mo (CO) (NO)PØ2R* (+)I and (‐)I is formed. The two diastereoisomers can be separated by preparative liquid chromatography; the less soluble isomer can also be obtained optically pure by several fractional crystallisations. The asymmetric induction of the group R* on the substitution of the enantiotopic CO ligands is only small; the two diastereoisomeric complexes (+)I and (‐)I are obtained in nearly equimolar amounts. The compounds are configurationally stable in solution even in the presence of nucleophiles like triphenylphosphine and isonitriles.The amino phosphine ligand in C5H5Mo(CO) (NO)PØ2R* can be transformed into the methoxy phosphine ligand P(C6H5)2OCH3 by reaction with HCl followed by addition of CH3OH.

Transformed steroids Communication 58. Epoxidation of divinyl ketones of steroid series

1. A study was made of the oxidation of divinyl ketones of the steroid series with alkaline hydrogen peroxide in various solvents: the most suitable variation for preparing the diepoxides is epoxidation in dioxane. Running the reaction in methanol yields a complex mixture of compounds, the main component of which is 16α,17α;-epoxy-21-methoxymethylpregn-5-en-3Β-ol-20-one 3-acetate (IV), the product of the primary addition of CH3OH to the more reactive unsubstituted δ21 bond and subsequent epoxidation of the δ16 bond. The formation of a noticeable amount of 16α,17α-epoxy-21-homopregna-5,21-dien-3/gb-ol-20-one 3-aeetate is observed after chromatographing on florisil. 2. 16α,17α-Epoxy-21-alkoxymethylpregn-4-ene-3,20-diones (XIIIa-c) were obtained by two methods.