Reaction Of Sulfide Research Articles

Mineralization of the Luanling gold deposit in the southern margin of the North China Craton: Insights from mineralogy and mineral chemistry of sulfides, tellurides and oxides

The Luanling gold deposit, a typical Te‐Au deposit in the Xiong'er terrane, the southern margin of the North China Craton, contains two types of ores, namely altered rock‐type and quartz vein‐type ores. Gold is hosted by pyrite and As‐bearing pyrite in the altered rock‐type ores, whereas tellurides are the main gold carriers in the quartz vein‐type ores. In order to investigate their origins, we calculated the Gibbs free energies of formation and reaction of related sulfides, tellurides and oxides from different ore types. The phase diagrams of these minerals were constructed at 300 °C, a temperature at which gold was mainly precipitated in the Luanling deposit. According to phase relations among sulfides, logfS2(g) is constrained between −10.4 and −6.5. In addition, we propose that [Au(HS)2]− was the dominant carrier of gold in ore‐forming fluid, and its decomposition formed pyrite and arsenian pyrite, in which gold mainly exists as an invisible phase. In the quartz vein‐type ores, logfTe2(g) and logfO2(g) are constrained to range from −13.68 to −7.9 and −36.8 to −31.1, respectively, based on the phase relations between tellurides, sulfides and oxides, and gold was mainly transported as [Au(HTe)2]− and its break down formed gold‐bearing, including sylvanite, petzite and Au‐Ag‐tellurides. Sylvanite and petzite, the two stable Au‐Ag tellurides, were probably precipitated primarily from hotter ore‐forming fluids. According to phase relations among tellurides, the two phases were decomposed into native gold, hessite and more stable Au‐Ag‐tellurides with the changes of physicochemical conditions in the later stages. In addition, we proposed that the ore‐forming fluids relevant to the altered rock‐ and the quartz vein‐type ores were from the same source and continuously evolved.

Oxidation of sulfide removal from petroleum refinery wastewater by using hydrogen peroxide

Petroleum refinery wastewater typically has high concentration of sulfide which is known as the most hazardous pollutants. It is released to the environment either as dissolved sulfide (S2- and HS−) in effluents or as H2S in waste gases. The objective in this study is to determine the effectiveness of hydrogen peroxide (H2O2) in sulfide removal. The best sulfide concentration, dosage and reaction time were determined. The removal of sulfide from petroleum refinery wastewater via oxidation method by using hydrogen peroxide (H2O2) is presented in this study. The treated wastewater was analyzed by spectrophotometer. Result shows that the best concentration of sulfide simulated wastewater (300 mg/L), H2O2 dosage (1.5 ml) and reaction time (30 min) able to reduce 97.67%, 98.22% and 98.89% of sulfide concentration from simulated wastewater. Thus, sulfide removal from the actual petroleum refinery wastewater which is spent caustic by using H2O2 was able to reduce 99.83% (0.5 mg/L) sulfide concentration. Besides that, Chemical Oxygen Demand (COD) concentration was reduced to 98.29% (70 mg/L) and pH 8.41 after treatment. Thus, it is concluded that oxidation method by using H2O2 is effective in sulfide removal as well as COD, and pH from spent caustic. It does meet requirement from Department of Environment (DOE) for sulfide, COD and pH which are 0.5 mg/L, 100 mg/L and 5.5 – 9.0, respectively. The information obtained from this study is useful for scale up purpose in the petroleum refining industry that choose H2O2 via oxidation method to remove sulfide from spent caustic wastewater.

Iterative oxidation and sulfidation reactions: revival of bulk cobalt sulfide into an active electrocatalyst for the oxygen evolution reaction

A thermal route based on iterative oxidation and sulfidation reactions opens a new way to revive a bulk sulfide into an active electrocatalyst that would have otherwise performed poorly for the oxygen evolution reaction.

Photoredox chemistry in the synthesis of 2-aminoazoles implicated in prebiotic nucleic acid synthesis.

Prebiotically plausible ferrocyanide-ferricyanide photoredox cycling oxidatively converts thiourea to cyanamide, whilst HCN is reductively homologated to intermediates which either react directly with the cyanamide giving 2-aminoazoles, or have the potential to do so upon loss of HCN from the system. Thiourea itself is produced by heating ammonium thiocyanate, a product of the reaction of HCN and hydrogen sulfide under UV irradiation.

Oxidation-sulfidation attacks on alloy 600 in supercritical water containing organic sulfides

The corrosion characteristics of alloy 600 in supercritical water containing organic sulfides was investigated after an exposure at 480 °C and 25 MPa for 72 h. A duplex-structure corrosion scale was observed, with the outer layer predominantly consisting of NiS. The inner corrosion layer was composed of Cr-rich spinel oxides and the fast channels (resulting from the interconnected sulfidation productions such as NiS and Ni3S2) for outward transport of metal cations. This phenomenon can be attributed to the emulative oxidation-sulfidation of alloy 600 because the supercritical water containing organic sulfides system may become a mixture of dominant SCW and H2S due to the gasification reaction of organic sulfides. The formation and growth processes of corrosion scales was also discussed.

Desulfurization of hexyl sulfide and hexanethiol using supercritical water

Desulfurization of hexyl sulfide and hexanethiol using supercritical water (SCW) was investigated by combining experimental and computational methods to study the desulfurization of alkyl sulfides and thiols in SCW. Desulfurization was conducted for 0 ∼ 30 min at 400 °C using thermal decomposition and SCW decomposition (24.7 ∼ 25.6 MPa), and the reaction pathways were built using the automated Reaction Mechanism Generator (RMG) and Gaussian 09. In thermal decomposition, C6-hydrocarbons (hexane, hexene) are main products, but in SCW, C5-hydrocarbon (pentane) in addition to C6-hydrocarbons are main products with higher alkane to alkene ratio. For the reaction pathways, in SCW, water participates as catalysts and reactants donating hydrogens with inhibited production of cyclic sulfides while in thermal decomposition, the hydrogen was deficient producing aromatic sulfur compounds such as thiophenes and alkyl-thiacycloalkanes. This study is expected to clarify the decomposition reactions of alkyl sulfides and alkyl thiols in SCW.

Formation of a U(VI)-Persulfide Complex during Environmentally Relevant Sulfidation of Iron (Oxyhydr)oxides.

Uranium is a risk-driving radionuclide in both radioactive waste disposal and contaminated land scenarios. In these environments, a range of biogeochemical processes can occur, including sulfate reduction, which can induce sulfidation of iron (oxyhydr)oxide mineral phases. During sulfidation, labile U(VI) is known to reduce to relatively immobile U(IV); however, the detailed mechanisms of the changes in U speciation during these biogeochemical reactions are poorly constrained. Here, we performed highly controlled sulfidation experiments at pH 7 and pH 9.5 on U(VI) adsorbed to ferrihydrite and investigated the system using geochemical analyses, X-ray absorption spectroscopy (XAS), and computational modeling. Analysis of the XAS data indicated the formation of a novel, transient U(VI)-persulfide complex as an intermediate species during the sulfidation reaction, concomitant with the transient release of uranium to the solution. Extended X-ray absorption fine structure (EXAFS) modeling showed that a persulfide ligand was coordinated in the equatorial plane of the uranyl moiety, and formation of this species was supported by computational modeling. The final speciation of U was nanoparticulate U(IV) uraninite, and this phase was evident at 2 days at pH 7 and 1 year at pH 9.5. Our identification of a new, labile U(VI)-persulfide species under environmentally relevant conditions may have implications for U mobility in sulfidic environments pertinent to radioactive waste disposal and contaminated land scenarios.

Simultaneous capture of NH3 and H2S using TiO2 and ZnO nanoparticles - laboratory evaluation and application in a livestock facility

Simultaneous removal of ammonia (NH3) and hydrogen sulphide (H2S) from pre-mixed gases and stored swine manure gases were investigated in laboratory and semi-pilot scale systems and in a swine production facility, using TiO2 and ZnO nanoparticles. Increase of NH3 concentration in the mixture from 50 to 500 ppmv led to higher breakthrough and equilibrium adsorption capacities, while increase of temperature had an opposite effect. Equilibrium adsorption capacities at 22 °C were in the range 6.92–11.95 mg NH3 g−1 and 1.35–3.57 mg NH3 g−1 at 280 °C. Increase of H2S concentration up to a certain level led to higher equilibrium adsorption capacities but no dependency between breakthrough adsorption capacity and H2S concentration was observed. Both breakthrough and equilibrium adsorption capacities increased with the increase of temperature. The highest equilibrium adsorption capacity of 52.31 mg H2S g−1 was obtained with 550 ppmv H2S in the mixture at 140 °C, while the lowest value was 14.55 mg H2S g−1 with 50 ppmv H2S at 22 °C. At low temperature (22 °C) NH3 adsorption occurred through both physical adsorption and chemisorption, while at 280 °C chemisorption was the dominant mechanism. A sulfidation reaction involving ZnO and H2S that was favored by higher temperatures was evident. Treating gases emitted from stored swine manure in a semi-pilot scale adsorption system led to complete elimination of NH3 and H2S. Application of a nano-based air filtration-circulation system with ZnO and TiO2 nanoparticles in a swine production room during manure handling led to removal efficiencies of 67–100% for H2S and 50–100% for NH3.

Mesoporous Zn-Fe-based binary metal oxide sorbent with sheet-shaped morphology: Synthesis and application for highly efficient desulfurization of hot coal gas

Mesoporous Zn-Fe-based binary metal oxide sorbent for hot coal gas desulfurization was derived from the Zn-Fe-based layer double hydroxide (ZnFe-LDH). Considering the great disparity of the pH required for the precipitation of Zn2+ and Fe3+, a two-step approach, namely the co-precipitation (Zn2+ and Fe2+) plus subsequent H2O2 oxidation, was proposed for the synthesis of the ZnFe-LDH, the precursor of the sorbent. The preliminary synthesis mechanism of the ZnFe-LDH was discussed. The results reveal that the formation of the layered structure occurs during the oxidation step process rather than the precipitation stage. A series of LDH-derived double metal oxides (DMOs) with the Zn/Fe molar ratios ranging from 1:1 to 5:1 were obtained and contain both ZnO and ZnFe2O4. Furthermore, sheet-shaped morphology is observed for most of the DMOs. The desulfurization performance of the DMOs was evaluated over a fixed-bed reactor. The results indicate that the DMO with the Zn/Fe molar ratio of 5:1 performs best and has the highest sulfur capacity (25 g of sulfur per 100 g of sorbent) at 550 °C. The reaction kinetics was analyzed via the deactivation model. The sorbent has lower deactivation rate constants (0.0185–0.0282 min−1) compared to other Zn-based sorbents, beneficial for the sulfidation reaction. In comparison to ZnO, the DMO sorbent shows lower regeneration temperature. Furthermore, regeneration could effectively recover the plugged pore structure caused by the sulfidation reaction. In addition, the sorbents could maintain high sulfur capacity during four sulfidation-regeneration cycles, showing great potential for industrial desulfurization of hot coal gas.

Aluminum promoted sulfidation of ammonium perrhenate: Presence of nanobattery in the ReS2 composite material based memcapacitor

This study demonstrates a new approach to the synthesis of rhenium disulfide (ReS2) in a sulfidation reaction of ammonium perrhenate (NH4ReO4), occurring at room temperature and in water solution. It was found that aluminum (Al) plays a catalytic role in the reaction taking place in low ionic strength solutions. The reaction product is characterized using several analysis techniques, including energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy and thermogravimetric analysis (TGA). Furthermore, an interesting observation of both memristive and memcapacitive effects, existence of nanobattery with an electromotive force estimated to be 0.80 V, in a prototypical device based on the as-synthesized ReS2 composite material is presented. This finding shows promise for the implementation of the ReS2 in the next generation memristor technology.

Carbozincation of Substituted 2-Alkynylamines, 1-Alkynylphosphines, 1-Alkynylphosphine Sulfides with Et2Zn in the Presence of Catalytic System of Ti(O-iPr)4 and EtMgBr

The EtMgBr and Ti(O-iPr)4-catalyzed ethylzincation of 1-alkynylphosphine sulfides with Et2Zn in diethyl ether followed by hydrolysis and deuterolysis affords corresponding β,β-disubstituted 1-alkenylphosphine sulfides with high yield. The EtMgBr and Ti(O-iPr)4-catalyzed reaction of 2-alkynylamines, 1-alkynylphosphines, and 1-alkenylphosphine sulfides with Et2Zn in various solvents was studied. It has been found that the reaction of 2-alkynylamines and 1-alkynylphosphines in methylene chloride, hexane, toluene, benzene, and anisole leads to the selective formation of 2-alkenylamines and 1-alkenylphosphine oxides after oxidation with H2O2.

Hydrogen Sulfide in Wastewater Generated by Hydrogen Induced Cracking Test: Cause and Safety Measures

During the process of treating various wastewater, toxic gas such as hydrogen sulfide is generated due to the chemical reaction among unknown chemicals contained in wastewater, causing an accident that kills or injures workers and requires evacuation of people in neighboring areas. This study tested the reaction of sodium hydrogen sulfide generated during hydrogen induced cracking with sulfuric acid to confirm the occurrence of hydrogen sulphide and proposed safety countermeasures to prevent similar disasters from recurring. Hydrogen sulphide gas used during the process of hydrogen organic crack test reacts with sodium hydroxide in a neutralization tank and a gas scrubber to produce sodium hydrogen sulphide. Highly toxic hydrogen sulphide gases are produced violently when wastewater containing sodium hydrogen sulfide is mixed with sulfuric acid wastewater. In order to prevent the occurrence of harmful gases due to adverse reactions during wastewater treatment, the process of generating consigned wastewater should be well identified in advance, along with the detailed information on the composition and properties of the wastewater. In addition, more attention should be paid to adverse reactions of mixed wastewater.

C-H Halogenation of Pyridyl Sulfides Avoiding the Sulfur Oxidation: A Direct Catalytic Access to Sulfanyl Polyhalides and Polyaromatics.

Palladium-catalyzed oxidative C–H halogenation and acetoxylation reactions of S-unprotected sulfides, selectively directed by pyridinyl groups, allows the formation of C–X bonds (X = I, Br, Cl, OAc) by using simple halosuccinimide or phenyliodine diacetate (PIDA) oxidants. The undesired formation of sulfoxides and/or sulfones, which are usually observed under oxidative conditions, is fully obviated. Under the solvent-dependent conditions that we proposed, sulfide C–H functionalization is achieved in less than 1 h without any direct electrophilic halogenation at the pyridine moiety. N-Directed ortho-C–H activation of aryl also facilitates dibromination reactions which are hardly accessible with sulfone and sulfoxide counterparts because of their higher structural rigidity. This general method gives a straightforward access to polyhalide sulfides, without an organosulfur reduction step or protection–deprotection sequence. Polyhalide sulfides are valuable synthons that give a practical entry to new constrained polyaromatic and biphenyl sulfides, including synthetically challenging unsymmetrical examples.

Lewis Acid Dominant Windmill-Shaped V8 Clusters: A Bifunctional Heterogeneous Catalyst for CO2 Cycloaddition and Oxidation of Sulfides.

Carbon dioxide (CO2) and sulfides in gasoline are the main causes of air pollution. Considerable attention has been devoted to solving the problems, and the catalytic reaction seems to be a good choice. Owing to the high density of Lewis acid (LA) active sites and large numbers of open methoxide groups, polyoxovanadates (POVs) are an undisputed option as a heterogeneous catalyst for the CO2 cycloaddition reaction and catalytic oxidation of sulfides. On the basis of the above, a series of V8 clusters, [(C2N2H8)4(CH3O)8VIV8O12]·CH3OH (V8-1a), [(C2N2H8)4(CH3O)4VIV4VV4O16]·4CH3OH (V8-1), [(C3N2H10)4(CH3O)4VIV4VV4O16]·5H2O (V8-2), [(C6N2H14)4(CH3O)4VIV4VV4O16]·5CH3OH·2H2O (V8-3), have been legitimately designed and triumphantly isolated. In the synthesis process, three different kinds of Lewis bases (LBs), ethanediamine, 1,2-diaminopropane, and 1,2-cyclohexanediamine, were used to modify LA {V8} clusters to form four diverting windmill-shaped configuration. Among them, the vanadium atoms in V8-1a are +4 valence of VIV, while the vanadium atoms in V8-1-3 are mixed valence states of VIV and VV. Magnetic property investigation indicates that the antiferromagnetic coupling interactions between VIV ions all exist in the four compounds. The compound V8-1 also demonstrated high catalytic activity in the cycloaddition of CO2 to several epoxides under relatively mild conditions (70 °C, 0.5 MPa). More importantly, the reaction pressure 0.5 MPa is the lowest among the high nuclear polyoxometallates (POMs). Furthermore, V8-1 also has an excellent catalytic conversion for the oxidation of sulfides. The catalytic tests manifested that V8-1 was a very efficient difunctional heterogeneous catalyst for CO2 cycloaddition reaction and catalytic oxidation of sulfides.

Ammonium chloride catalyze sulfidation mechanism of smithsonite surface: Visual MINTEQ models, ToF-SIMS and DFT studies

NH3-based promoting sulfidation have attracted attention for smithsonite surface sulfidation, but the role of the NH3/zinc/sulphur interface in promoting this chemistry remains under debate. Herein, we combined Visual MINTEQ models, ToF-SIMS and DFT to elucidate the impact of this interface on smithsonite surface sulfidation. The results demonstrated that the addition of ammonium chloride caused the CZnT in the pulp solution to increase. After the sulfidation reaction between zinc ammonium complex ions and HS− ions, accompanying the deeper conversion from ZnS(aq), Zn2S32− and Zn4S64− ions to sphalerite, more sphalerite was formed. ToF-SIMS analysis provided strong evidence for an increase in the zinc sulfide species on the smithsonite surface with the addition of NH4Cl, and the thickness of formed zinc sulfide species was approximately 26.66 nm. DFT study confirmed that NH3 acted a catalytic role during the smithsonite surface sulfidation processing including ion-exchange reaction and sphalerite precipitation adsorption. The presence of NH3 changed the reaction pathway from Zn(OH)2 + HS− → ZnS to Zn(OH)2 → Zn(NH3)42+ + HS− → ZnS and decreased the total energy barriers from 90.46 kcal/mol to 65.31 kcal/mol. Additionally, the NH3 promoted the sulphur migration from HS− to Zn with a lower energy barrier to form the ZnS spontaneously.

Construction of sugar gourd-like yolk-shell Ni–Mo–Co–S nanocage arrays for high-performance alkaline battery

Mixed transition metal sulfides (TMSs) with hollow and complex hollow structures have attracted intensive attentions as high-performance cathode materials for rechargeable alkaline batteries. However, these powder-based electrode materials should be further mixed with insulative polymer binders and suffered from complicate electrode fabrication process. Herein, for the first time, we demonstrate the delicate design and synthesis of the sugar gourd-like multi-component yolk-shell Ni–Mo–Co–S nanocage arrays (NCAs) on Ni foam (NF) through a facile metal-organic framework (MOF)-engaged strategy. The synthetic process includes the growth of Co-based zeolitic imidazolate framework (ZIF-67) polyhedra onto the NiMoO4·xH2O nanorod arrays (NRAs) at room temperature and followed by a sufficient sulfidation reaction. Benefiting from the intriguing structural and compositional advantages, the yolk-shell Ni–Mo–Co–S NCAs/NF binder-free electrode exhibits an extremely high areal capacity of 1.96 mAh cm−2 at a current density of 5 mA cm−2 and excellent cycling stability. The electrode kinetics analysis confirms the diffusion-controlled battery-type behavior of the yolk-shell Ni–Mo–Co–S NCAs/NF electrode. The corresponding full cell delivers an high energy density of 92.6 Wh kg−1 at the power density of 1029.1 W kg−1 with the yolk-shell Ni–Mo–Co–S NCAs/NF as cathode electrode and Bi2O3 as anode electrode, indicating the potential for real applications. This work would make contribution to the realization of directly growing multi-component hollow and complex hollow structures on conductive substrate for high-performance electrochemical energy storage.

MOF-Derived CuS@Cu-BTC Composites as High-Performance Anodes for Lithium-Ion Batteries.

The CuS(x wt%)@Cu-BTC (BTC = 1,3,5-benzenetricarboxylate; x = 3, 10, 33, 58, 70, 99.9) materials are synthesized by a facile sulfidation reaction. The composites are composed of octahedral Cu3 (BTC)2 ·(H2 O)3 (Cu-BTC) with a large specific surface area and CuS with a high conductivity. The as-prepared CuS@Cu-BTC products are first applied as the anodes of lithium-ion batteries (LIBs). The synergistic effect between Cu-BTC and CuS components can not only accommodate the volume change and stress relaxation of electrodes but also facilitate the fast transport of Li ions. Thus, it can greatly suppress the transformation process from Li2 S to polysulfides by improving the reversibility of the conversion reaction. Benefiting from the unique structural features, the optimal CuS(70 wt%)@Cu-BTC sample exhibits a remarkably improved electrochemical performance, showing an over-theoretical capacity up to 1609 mAh g-1 after 200 cycles (100 mA g-1 ) with an excellent rate-capability of ≈490 mAh g-1 at 1000 mA g-1 . The outstanding LIB properties indicate that the CuS(70 wt%)@Cu-BTC sample is a highly desirable electrode material candidate for high-performance LIBs.

Superior Lithium Storage Capacity of α‐MnS Nanoparticles Embedded in S‐Doped Carbonaceous Mesoporous Frameworks

AbstractHerein, a Mn‐based metal–organic framework is used as a precursor to obtain well‐defined α‐MnS/S‐doped C microrod composites. Ultrasmall α‐MnS nanoparticles (3–5 nm) uniformly embedded in S‐doped carbonaceous mesoporous frameworks (α‐MnS/SCMFs) are obtained in a simple sulfidation reaction. As‐obtained α‐MnS/SCMFs shows outstanding lithium storage performance, with a specific capacity of 1383 mAh g−1 in the 300th cycle or 1500 mAh g−1 in the 120th cycle (at 200 mA g−1) using copper or nickel foil as the current collector, respectively. The significant (pseudo)capacitive contribution and the stable composite structure of the electrodes result in impressive rate capabilities and outstanding long‐term cycling stability. Importantly, in situ X‐ray diffraction measurements studies on electrodes employing various metal foils/disks as current collector reveal the occurrence of the conversion reaction of CuS at (de)lithiation process when using copper foil as the current collector. This constitutes the first report of the reaction mechanism for α‐MnS, eventually forming metallic Mn and Li2S. In situ dilatometry measurements demonstrate that the peculiar structure of α‐MnS/SCMFs effectively restrains the electrode volume variation upon repeated (dis)charge processes. Finally, α‐MnS/SCMFs electrodes present an impressive performance when coupled in a full cell with commercial LiMn1/3Co1/3Ni1/3O2 cathodes.

Оценка возможности очистки технического кремния методом химического транспорта с сульфидом цинка

The demand for renewable energy sources, including solar, is increasing every year, stimulating researchers to develop innovative technological solutions for obtaining material for photovoltaic modules - solar silicon. The article discusses a new process for the vapor transport of silicon in the form of sulfide compounds, which can serve as the basis for a halogen-free technology for producing high-purity silicon for photovoltaic batteries. Considering the well-known properties of silicon di- and monosulfide, it is proposed to use zinc sulfide as a carrier reagent, the presence of which in the Si-ZnS system first provides silicon sulfidization with the formation of gaseous products Zn (g) and SiS (g), and then the reduction of monosulfide to elemental silicon. The possibility of a chemical vapor transport reaction of silicon with zinc sulfide at a temperature above 1000 °C and a Si/ZnS ratio of 1 was justified by the method of the thermodynamic simulation of interactions in the Si-ZnS system in the temperature range 500-1500 °C. Based on the obtained equilibrium models of the interaction of zinc sulfide with technical silicon (grade Kr 2), the separation coefficients of (α) silicon from impurity elements that affect the electrophysical properties of silicon, in particular, reduce the lifetime of excess charge carriers, are calculated. The selectivity of this transport reaction and the prospects for its use for refining metallurgical silicon are estimated. It has been shown that the use of the silicon transfer reaction of zinc sulfide, for example, at 1100 °C, can provide deep purification of silicon from Fe, Ca, Ti, V, Cr, Mn and Cu (α ~ 108-1012), as well as Mg and Al (α ~ 104-106). The process is less effective for removing P and B (α ~ 102) and is not applicable for alkali metals in the entire studied temperature range. It is theoretically possible to improve the refining indexes by lowering the reaction temperature, but the necessary sulfur concentration in the gas phase for the complete conversion of silicon to SiS (g) is achieved only above 1050-1100 oC due to thermal dissociation of ZnS.

Regioselective hydroxylation pathway of tenatoprazole to produce human metabolites by Bacillus megaterium CYP102A1

Abstract Tenatoprazole, a proton pump inhibitor drug candidate, is developed as an acid inhibitor to treat gastric acid hypersecretion disorders, such as gastric ulcer and reflux esophagitis. Tenatoprazole is known to be metabolized to three major metabolites—tenatoprazole sulfone, 5’-hydroxylated metabolite, and tenatoprazole sulfide—in human livers mainly by CYP2C19 and CYP3A4. In this study, an enzymatic strategy for the production of human metabolites of tenatoprazole was developed using bacterial P450 enzymes. A set of CYP102A1 mutants catalyzed the regioselective hydroxylation reactions of tenatoprazole. The major product of tenatoprazole by CYP102A1 is 5’-OH tenatoprazole, a major human metabolite produced by human CYP2C19 and CYP3A4. As another major metabolite of tenatoprazole, tenatoprazole sulfide is formed via a non-enzymatic conversion without a P450 system. In addition, 5’-OH tenatoprazole sulfide was found as a minor metabolite, which can be formed via a 5’-hydroxylation reaction of tenatoprazole sulfide by CYP102A1 and/or a non-enzymatic reduction of 5’-OH tenatoprazole to a sulfide form. Chemical synthesis of the 5’-OH tenatoprazole is not currently possible. In conclusion, an enzymatic synthesis of 5’-OH tenatoprazole, a major human metabolite of tenatoprazole, was developed by using mutants of CYP102A1 from Bacillus megaterium as a biocatalyst and tenatoprazole as a substrate.