Method For Deoxygenation Research Articles

Selective Deoxygenation of Pyridine N‐Oxides through Photoredox Catalysis of a Dilacunary Silicotungstate

AbstractIn this paper, we report a highly selective and widely applicable method for deoxygenation of pyridine N‐oxides using ethanol as the reducing agent through the visible‐light‐responsive photoredox catalysis of a divacant lacunary silicotungstate TBA4H4[γ‐SiW10O36] (I, TBA=tetra‐n‐butylammonium). By irradiation with visible light (λ > 385 nm), the two‐electron and two‐proton transfers from the coordinated ethanol to I efficiently took place. Then, the transiently stored electrons and protons within I could be effectively utilized for the selective deoxygenation of pyridine N‐oxides. Various kinds of structurally diverse pyridine N‐oxides could be converted into the corresponding substituted pyridines in high yields, even in the presence of other reducible functional groups, such as olefinic, chloro, cyano, carbonyl, and amide groups. In addition, I could be readily retrieved after the reaction, and the retrieved I could be reused with keeping its high catalytic performance. The lacunary site of I played an important dual role as the electron transfer site from ethanol to I and the selective electron transfer site from the reduced I to pyridine N‐oxides.

Catalytic deoxygenation of high-purity water using membrane electrode units

A new method for water deoxygenation using membrane technologies was suggested. The method is based on electrochemical reduction of dissolved oxygen on the surface of membrane electrode units in combination with its chemical reduction with hydrogen on a catalytically active sorbent. A pilot setup for deoxygenation of high-purity water with the output of up to 200 L h–1 was developed on the basis of the results obtained.

Production of liquid hydrocarbons from pretreated bio-oil via catalytic deoxygenation with syngas

Biomass-derived fast pyrolysis oil (bio-oil) is a potential alternative replacement for conventional transportation fuels. But negative properties such as lower energy density, higher water content and acidity prevent the direct use of pyrolysis oil as a fuel. Catalytic deoxygenation of pyrolysis oils to hydrocarbons has been studied widely with application of high heat and hydrogen pressure. However, consumption of a large amount of expensive hydrogen has remained a problem for this technology. Therefore, development of an efficient and reduced hydrogen deoxygenation method would be desirable. In this study, we have applied catalytic deoxygenation of pretreated bio-oil in the presence of pressurized syngas to produce liquid hydrocarbons. The pretreatment is an oxidation step that converts aldehydes to carboxylic acids that are more conducive to catalytic conversion to hydrocarbons than are raw bio-oils. The pretreated bio-oil allowed performance of a partial deoxygenation step with a low amount of hydrogen (syngas). This partially deoxygenated product was then fully deoxygenated with pure hydrogen to produce hydrocarbons. Properties of the resultant liquid hydrocarbons were analyzed by ASTM standards for transportation fuels. The hydrocarbon mixture obtained by our process was analyzed by Fourier transform infrared spectroscopy, detailed hydrocarbon analysis, nuclear magnetic resonance spectroscopy and simulated distillation.

Deoxygenation of oleic acid over Ce(1–x)Zr(x)O2 catalysts in hydrogen environment

Ce(1–x)Zr(x)O2 catalysts were prepared by co-precipitation method for deoxygenation (DO) of oleic acid. The CeO2/ZrO2 ratio was systematically varied to optimize Ce(1–x)Zr(x)O2 catalysts. Ce0.6Zr0.4O2 exhibited the highest oleic acid conversion as well as high selectivity to C9 ∼ C17 compounds (diesel fuel range) at the reaction temperature of 300 °C. The high activity/selectivity of Ce0.6Zr0.4O2 catalyst was correlated to its reducibility, oxygen storage capacity and crystallite size.

Selective Deoxygenation of Allylic Alcohol: Stereocontrolled Synthesis of Lavandulol

Selective deoxygenation of allylic alcohol can be successfully carried out by the formation of alkoxyalkyl ether (EE or MOM), followed by Pd(dppe)Cl(2)-catalyzed reduction with LiBHEt(3). (+)-S-Lavandulol has been efficiently synthesized by the application of this protocol to the diol derived from the Pb(OAc)(4)-promoted oxidative ring-opening of (-)-R-carvone. This deoxygenation method is general and selective for allylic alcohols.

ChemInform Abstract: New Deoxygenation Method for Amine N‐Oxides Using Dimethylthiocarbamoyl Chloride.

A facile and efficient deoxygenation method for various amine N-oxides to their corresponding amines is described. The experimental procedure is quite simple and the products are obtained in excellent yields.

New Deoxygenation Method for Amine N-Oxides Using Dimethylthiocarbamoyl Chloride

A facile and efficient deoxygenation method for various amine N-oxides to their corresponding amines is described. The experimental procedure is quite simple and the products are obtained in excellent yields.

A Direct, Biomass‐Based Synthesis of Benzoic Acid: Formic Acid‐Mediated Deoxygenation of the Glucose‐Derived Materials Quinic Acid and Shikimic Acid

Shikimic Gimmick: An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

Water treatment for steam generators with the aid of ion exchangers

A method for simultaneous desalting and deoxygenation of feed and extra water was developed for through steam generators using ion-exchange mixed bed filters and the filter with ferrous hydroxide electron ion exchanger which eliminates the stage of thermal deaeration.

A study of the electret state of polyethylene formulations with a ferroelectric

A method for simultaneous desalting and deoxygenation of feed and extra water was developed for through steam generators using ion-exchange mixed bed filters and the fi lter with ferrous hydroxide electron ion exchanger which eliminates the stage of thermal deaeration.

Deoxygenation of Pyridine N-Oxides by Palladium-Catalysed Transfer ­Oxidation of Trialkylamines

A convenient and chemoselective method for deoxygenation of pyridine N-oxide derivatives by transfer oxidation of triethylamine-catalysed by [Pd(OAC) 2 ]/dppf is described.

Expedited Approach to the Vitamin D trans-Hydrindane Building Block from the Hajos Dione. Comparative Study on Various Methods for the Selective Deoxygenation of One of the Hydroxy Groups in a Diol

1 alpha,25-Dihydroxyvitamin D3 (calcitriol, 1) is a bioregulator important for the treatment of various human metabolic diseases and biomedical research. Herein, we report an efficient diastereoselective approach to the key trans-hydrindane building block for calcitriol synthesis (2a) starting from the readily accessible optically active tetrahydroindenedione derivative (Hajos dione, 3). It was found that epoxide ring opening in a related hydroxy epoxide (7) with sodium cyanoborohydride-BF3 x Et2O occurs by hydride anion addition at the ring juncture position to produce a vicinal diol with the trans-hydrindane ring system (6a). Four methods for selective deoxygenation of the sterically less shielded hydroxy group in diol 6a were examined with an approach based on a cyclic sulfate of the diol as the most efficient and operationally convenient method.

Ship board testing of a deoxygenation ballast water treatment

A ship board trial of a deoxygenation method for treating ballast water was carried out during a voyage from Southampton (United Kingdom) to Manzanillo (Panama). A nutrient solution added to two ballast tanks encouraged bacterial growth, resulting in a gradual change to an anoxic environment. Samples were taken from two treated tanks and two untreated tanks to assess changes in the abundance and viability of zooplankton, phytoplankton and bacteria. The work was carried out before the International Maritime Organization (IMO) standard was agreed so only a broad indication of whether the results achieved the standard was given. For the zooplankton, the standard would have been achieved within 5 or 7 days but the phytoplankton results were inconclusive. The biological efficacy was the result of the combination of several factors, including the treatment, pump damage and an increase in the water temperature during the voyage.

Some thermal engineering aspects of protecting the condensate-feedwater path of a cogeneration station against corrosion

Questions pertinent to making the thermal deaeration of feedwater flows more energy efficient, the advisability of using chemical methods for final deoxygenation of feedwater, and checking the tightness of vacuum systems used in turbine units are considered.

Pd/C-Catalyzed Deoxygenation of Phenol Derivatives Using Mg Metal and MeOH in the Presence of NH4OAc

A Pd/C-catalyzed deoxygenation method of phenolic hydroxyl groups via aryl triflates or mesylates using Mg metal in MeOH at room temperature was developed. The addition of NH4OAc dramatically affects the reactivity and reaction rate. This method is particularly attractive to provide an environmentally benign and widely applicable removal method of phenolic alcohols under quite mild reaction conditions.

Rapid Mo(CO) 6 catalysed one-pot deoxygenation of heterocyclic halo-benzyl alcohols with Lawesson’s reagent

A fast and efficient microwave promoted one-pot method for deoxygenation of heterocyclic halo-benzyl alcohols has been developed. The method does not cause dehalogenation of the substrates and provides the deoxygenated products in high yield after only 30 min.

Synthesis of d-rubranitrose by using a novel method for constructing functionalized branched-chain structures

Convenient synthesis of d-rubranitrose from d-glucose was achieved by using simple and novel methods for deoxygenation and construction of functionalized branched-chain structures. The total yield of d-rubranitrose from methyl 4,6-O-benzylidene-α-d-glucopyranoside (1) was 4.9%.

An Industrial Process for Synthesizing Lodenosine (FddA)

Two industrial synthetic approaches to Lodenosine (1, FddA, 9-(2,3-dideoxy- 2-fluoro-β-D-threo-pentofuranosyl) adenine) via a purine riboside or a purine 3′-deoxyriboside are described. Several novel applications of deoxygenation and fluorination methods are compared considering reaction yields, economy, safety and environmental concerns.

Novel and convenient method for the syntheses of 2,6-dideoxypyranoses, 3,6-dideoxypyranoses, and azido (amino) analogs of 3,6-dideoxypyranoses

A novel method of regioselective deoxygenation of methyl 4,6- O-benzylidene-2,3-di- O-tosyl-α- d-glucopyranoside, and its application for the syntheses of 2,6-dideoxypyranoses, 3,6-dideoxypyranoses, and azido (amino) analogs of 3,6-dideoxypyranoses were reported.

A Concise and Enantioselective Synthesis of a C-6 O-Acyl Side Chain Equivalent of Zaragozic Acid A.

An optically pure C-6 O-acyl side chain equivalent of zaragozic acid A, (2E, 4S, 6S)-4, 6-dimethyl-2-octenoic acid, which features a 1, 3-syn-dimethyl-substituted carbon chain, has been readily synthesized from (S)-2-methylbutanal using a combination of the Evans aldol reaction and the Ireland deoxygenation method.