A Convenient Way for the Synthesis of Mono N-Alkylated Ethanolamine

The thermal and catalytic conversion processes of alternative feedstocks (e.g., waste and biomass) to different engine fuels can result in the formation of a significant amount of light hydrocarbons as by-products in the boiling range of gasoline. The properties of these C5/C6 hydrocarbons need to be improved due to many reasons, e.g., their benzene content, and/or poor oxidation stability (high olefin content) and low octane number (<60). The aim of the research work was to increase the octane number of benzene containing C5/C6 bioparaffin fractions by catalytic isomerization. These by-products were obtained from special hydrocracking of waste cooking oil to hydrocarbons in the boiling range of aviation turbine fuels (JET fuels)/diesel fuels. Experiments were carried out in a reactor system containing down-flow tubular reactors over Pt/Al2O3/Cl and Pt/H-Mordenite/Al2O3 catalysts at 115–145 °C and 230–270 °C, respectively. Based on the results obtained at different process parameter combinations, it was concluded that the hydrogenation of benzene was complete over both catalysts, and the liquid yields were higher (ca. 98% > ca. 93 %) in the case of Pt/Al2O3/Cl. In addition, the octane number was also enhanced (ca. 32 > ca. 27 unit) in the products compared to the feedstock. This was because a higher isoparaffin content can be obtained at a lower operating temperature. Moreover, cracking side reactions take place to a lesser extent. The utilization of these isomerized bio-origin light fractions can contribute to the competitiveness of second-generation biofuels.

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A Convenient Way for the Synthesis of Mono N-Alkylated Ethanolamine

10.26434/chemrxiv.13031183.v1 ◽

2020 ◽

Author(s):

ZHE LI ◽

Changren Yan

Keyword(s):

Side Reactions ◽

By Products

N-alkylated ethanol amines, especially the N-monoalkylated ethanol amines, feature widely applications in industries. This manuscript would introduce a new methodology to prepare N-monoalkylated ethanol amine derivatives that could avoid potential side reactions forming N,N-dialkylated by-products.

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Alkylene oxide poylmerizations: identification of side reactions and by-products

Journal of Polymer Research ◽

10.1007/s10965-016-1141-z ◽

2016 ◽

Vol 23 (12) ◽

Cited By ~ 4

Author(s):

Muhammad Imran Malik ◽

Muhammad Irfan ◽

Akbar Khan ◽

Sana Rahim ◽

Rubina Abdul-Karim ◽

...

Keyword(s):

Side Reactions ◽

Alkylene Oxide ◽

By Products

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Synthesis of [18F]FAZA Using Nosyl and Iodo Precursors for Nucleophilic Radiofluorination

Current Radiopharmaceuticals ◽

10.2174/1874471011666181019105947 ◽

2019 ◽

Vol 12 (1) ◽

pp. 49-57

Author(s):

William Sun ◽

Cheryl Falzon ◽

Ebrahim Naimi ◽

Ali Akbari ◽

Leonard I. Wiebe ◽

...

Keyword(s):

Large Scale ◽

Side Reactions ◽

Automated Synthesis ◽

Complex Reaction ◽

Chemical Structures ◽

Standardized Protocol ◽

High Yields ◽

Automated Procedures ◽

Optimized Conditions ◽

By Products

Background: 1-α-D-(5-Deoxy-5-[18F]fluoroarabinofuranosyl)-2-nitroimidazole ([18F]FAZA) is manufactured by nucleophilic radiofluorination of 1-α-D-(2’,3’-di-O-acetyl-5’-O-toluenesulfonylarabinofuranosyl)- 2-nitroimidazole (DiAcTosAZA) and alkaline deprotection to afford [18F]FAZA. High yields (>60%) under optimized conditions frequently revert to low yields (<20%) in large scale, automated syntheses. Competing side reactions and concomitant complex reaction mixtures contribute to substantial loss of product during HPLC clean-up. Objective: To develop alternative precursors for facile routine clinical manufacture of [18F]FAZA that are compatible with current equipment and automated procedures. Methods: Two new precursors, 1-α-D-(2’,3’-di-O-acetyl-5’-O-(4-nitrobenzene)sulfonyl-arabinofuranosyl)-2- nitroimidazole (DiAcNosAZA) and 1-α-D-(2’,3’-di-O-acetyl-5’-iodo-arabinofuranosyl)-2-nitroimidazole (DiAcIAZA), were synthesized from commercially-available 1-α-D-arabinofuranosyl-2-nitroimidazole (AZA). A commercial automated synthesis unit (ASU) was used to condition F-18 for anhydrous radiofluorination, and to radiofluorinate DiAcNosAZA and DiAcIAZA using the local standardized protocol to manufacture [18F]FAZA from AcTosAZA. Results: DiAcNosAZA was synthesized via two pathways, in recovered yields of 29% and 40%, respectively. The nosylation of 1-α-D-(2’,3’-di-O-acetyl-arabinofuranosyl)-2-nitroimidazole (DiAcAZA) featured a strong competing reaction that afforded 1-α-D-(2’,3’-di-O-acetyl-5’-chloro-arabinofuranosyl)-2- nitroimidazole (DiAcClAZA) in 55% yield. Radiofluorination yields were better from DiAcNosAZA and DiAcIAZA than from DiAcTosAZA, and the presence of fewer side products afforded higher purity [18F]FAZA preparations. Several radioactive and non-radioactive by products of radiofluorination were assigned tentative chemical structures based on co-chromatography with authentic reference compounds. Conclusion: DiAcClAZA, a major side-product in the preparation of DiAcNosAZA, and its deprotected analogue (ClAZA), are unproven hypoxic tissue radiosensitizers. DiAcNosAZA and DiAcIAZA provided good radiofluorination yields in comparison to AcTosAZA and could become preferred [18F]FAZA precursors if the cleaner reactions can be exploited to bypass HPLC purification.

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The autoxidation of isopropylbenzenes to benzoic acids in acid media: III. Side-reactions and by-products

Recueil des Travaux Chimiques des Pays-Bas ◽

10.1002/recl.19610801113 ◽

2010 ◽

Vol 80 (11) ◽

pp. 1257-1277 ◽

Cited By ~ 6

Author(s):

R. van Helden ◽

A. F. Bickel ◽

E. C. Kooyman

Keyword(s):

Side Reactions ◽

Benzoic Acids ◽

Acid Media ◽

By Products

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The Synthesis of (Iodobenzyl)oxybenzaldehydes, Useful Intermediates for Biologically Active Targets

Letters in Drug Design & Discovery ◽

10.2174/1570180813666160804142245 ◽

2016 ◽

Vol 14 (2) ◽

pp. 233-239 ◽

Cited By ~ 1

Author(s):

Hedvig Bölcskei ◽

Andrea Német-Hanzelik ◽

István Greiner ◽

Zsófia Dubrovay ◽

Viktor Háda ◽

...

Keyword(s):

Reaction Time ◽

Double Bond ◽

High Resolution ◽

New Products ◽

Biologically Active ◽

Side Reactions ◽

Channel Blockers ◽

Voltage Gated ◽

High Yields ◽

By Products

The benzyloxy-benzyl moiety is a valuable building block in medicinal chemistry, e.g. in case of the voltage gated sodium channel blockers Safinamide and Ralfinamide. To prepare further derivatives a series of (iodobenzyl)oxybenzaldehydes (3a-3i) useful intermediates for the synthesis of biologically active compounds were synthesized in high yields by O-benzylation of 2-, 3- and 4- hydroxybenzaldehydes (2a-2c) with a variety of iodobenzylbromides (1a-1c). The title compounds were obtained in 77-100 % yield in 2-5 hours. Longer reaction time or addition of water favoured the formation of aldol-type by-products, mainly 4-hydroxy-4-{[(iodophenyl)methoxy]phenyl}butan-2-one derivatives (5a-5g), which contained the iodine group and the 4-hydroxy-butan-2-one moiety in various positions. In one case (3E-)-4-{3-[(2-iodophenyl)methoxy]phenyl}but-3-en-2-one (6c) with a double bond has been isolated. These side-reactions could be avoided by using acetonitrile as solvent. The structures of the new products were established by high resolution MS and NMR measurements, where 1H-1H, direct 1H-13C, long-range 1H-13C scalar spin-spin connectivities were established from 1D 1H, 13C, 2D gHSQCAD, zTOCSY and gHMBCAD NMR experiments.

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A hydrophobic FeMn@Si catalyst increases olefins from syngas by suppressing C1 by-products

Science ◽

10.1126/science.abb3649 ◽

2021 ◽

Vol 371 (6529) ◽

pp. 610-613 ◽

Cited By ~ 4

Author(s):

Yanfei Xu ◽

Xiangyang Li ◽

Junhu Gao ◽

Jie Wang ◽

Guangyuan Ma ◽

...

Keyword(s):

Iron Carbide ◽

Side Reactions ◽

Co Conversion ◽

Olefin Production ◽

Oxidation By Water ◽

Multifunctional Catalyst ◽

By Products ◽

Hydrophobic Shell ◽

Made In ◽

Carbon Molecule

Although considerable efforts have been made in the selective conversion of syngas [carbon monoxide (CO) and hydrogen] to olefins through Fischer-Tropsch synthesis (FTS), ~50% of the converted CO is transformed into the undesired one-carbon molecule (C1) by-products [carbon dioxide (CO2) and methane (CH4)]. In this study, a core-shell FeMn@Si catalyst with excellent hydrophobicity was designed to hinder the formation of CO2 and CH4. The hydrophobic shell protected the iron carbide core from oxidation by water generated during FTS and shortened the retention of water on the catalyst surface, restraining the side reactions related to water. Furthermore, the electron transfer from manganese to iron atoms boosted olefin production and inhibited CH4 formation. The multifunctional catalyst could suppress the total selectivity of CO2 and CH4 to less than 22.5% with an olefin yield of up to 36.6% at a CO conversion of 56.1%.

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Synthese einer Partialsequenz aus dem aktiven Zentrum der Streptokokken-Proteinase (EC 3.4.22.10), IX / Synthesis of a Fragment of the Active Center of the Streptococcal Proteinase (EC 3.4.22.10), IX

Zeitschrift für Naturforschung C ◽

10.1515/znc-1976-7-815 ◽

1976 ◽

Vol 31 (7-8) ◽

pp. 418-423

Author(s):

Andreas Raschig ◽

Friedhelm Schneider

Keyword(s):

Active Center ◽

Trifluoroacetic Acid ◽

Crystalline State ◽

Partial Sequence ◽

Side Reactions ◽

Protective Group ◽

Streptococcal Proteinase ◽

By Products

Abstract The synthesis of the protected pentapeptide tert-butyloxycarbonyl-Gln-Ile-Met-Lys (X) -Gly-p-nitrobenzylester (X = benzyloxycarbonyl, 3-chlor-benzyloxycarbonyl) which is part of the carboxylend of a partial sequence of the active center of the streptococcal proteinase is described. Side reactions are observed if the tert-butyloxycarbonyl-protective group is cleaved by trifluoroacetic acid, not with HCl/dioxane. Obviously the presence of methionine is responsible for the formation of by products. Formation of methioninesulfoxide or tert-butylsulfoniummethionine could not be proved. tert-butyloxycarbonyl-Gln-1-hydroxybenzotriazolylester was obtained in a crystalline state from the reaction of ferf-butyloxycarbonyl-Gln, dicyclohexylcarbodiimid and 1-hydroxybenzotriazol.

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A Convenient Way for the Synthesis of Mono N-Alkylated Ethanolamine

10.26434/chemrxiv.13031183.v2 ◽

2020 ◽

Author(s):

ZHE LI ◽

Changren Yan

Keyword(s):

Side Reactions ◽

By Products

N-alkylated ethanol amines, especially the N-monoalkylated ethanol amines, feature widely applications in industries. This manuscript would introduce a new methodology to prepare N-monoalkylated ethanol amine derivatives that could avoid potential side reactions forming N,N-dialkylated by-products.

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Preparation of sub-microspherical Fe3O4@PDA-Pd NPs catalyst and application in catalytic hydroreduction reaction of halogenated aromatic nitro compounds to prepare halogenated aromatic amines

BMC Chemistry ◽

10.1186/s13065-019-0649-9 ◽

2019 ◽

Vol 13 (1) ◽

Cited By ~ 2

Author(s):

Haichang Guo ◽

Renhua Zheng ◽

Huajiang Jiang ◽

Zhenyuan Xu ◽

Aibao Xia

Keyword(s):

Aromatic Compound ◽

Aromatic Amine ◽

Atmospheric Pressure ◽

Aromatic Amines ◽

High Selectivity ◽

Nitro Compounds ◽

Side Reactions ◽

Aromatic Nitro Compounds ◽

Aromatic Nitro ◽

By Products

Abstract Background The side reactions of dehalogenation or C–N coupling tend to occur when halogenated aromatic amines are prepared by catalytic hydrogenation reduction of halogenated aromatic nitro compounds. In this paper, we prepared the sub-microspherical Fe3O4@PDA-Pd NPs catalyst apply it efficiently in the hydrogenation reduction of halogenated aromatic nitro compounds to prepare the halogenated aromatic amines under atmospheric pressure. The catalyst shows a high selectivity of greater than 96% and can effectively inhibit the occurrence of the side reactions of dehalogenation and C–N coupling. Results The optimum condition of the hydroreduction reaction is when tetrahydrofuran is used as solvent and the reaction happens at 50 °C for 5 h. The selectivity of the chlorinated aromatic amine and the fluorinated aromatic amine products exceed 99% and the yield exceeds 90%. Only a small amount of dehalogenated products and C–N coupling by-products were produced in the brominated aromatic compound and the iodinated aromatic compound. Conclusion We developed a promising method for preparing the superparamagnetic and strongly magnetic Fe3O4@PDA core–shell sub-microsphere-supported nano-palladium catalyst for catalyzing the hydrogenation reduction of halogenated aromatic nitro compounds. The halogenated aromatic amines were efficiently and highly selectively prepared under atmospheric pressure, with the side reactions of dehalogenation and C–N coupling effectively inhabited simultaneously.

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