scholarly journals Trace mild acid-catalysed Z→E isomerization of norbornene-fused stilbene derivatives: intelligent chiral molecular photoswitches with controllable self-recovery

2021 ◽  
Author(s):  
Taotao Hao ◽  
Yongsheng Yang ◽  
Wenting Liang ◽  
Chunying Fan ◽  
Xin Wang ◽  
...  
Keyword(s):  
Mineral Acid ◽  
Severe Reaction ◽  
Reaction Conditions ◽  
Strong Mineral Acid ◽  
Stilbene Derivatives ◽  
Acid Catalyzed ◽  
High Concentrations ◽  
Mild Acid

Stilbene derivatives are long known to undergo “acid-catalyzed” Z→E isomerization, where a strong mineral acid in high concentrations is practically demanded. Such severe reaction conditions often cause undesired by-reactions and...

scholarly journals Recent Development in Chemical Depolymerization of Lignin: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hai Wang ◽  
Melvin Tucker ◽  
Yun Ji
Keyword(s):  
High Pressure ◽  
Ionic Liquids ◽  
Supercritical Fluids ◽  
High Selectivity ◽  
Severe Reaction ◽  
Great Contribution ◽  
Reaction Conditions ◽  
Commercial Scale ◽  
High Pressure High Temperature ◽  
Acid Catalyzed

This article reviewed recent development of chemical depolymerization of lignins. There were five types of treatment discussed, including base-catalyzed, acid-catalyzed, metallic catalyzed, ionic liquids-assisted, and supercritical fluids-assisted lignin depolymerizations. The methods employed in this research were described, and the important results were marked. Generally, base-catalyzed and acid-catalyzed methods were straightforward, but the selectivity was low. The severe reaction conditions (high pressure, high temperature, and extreme pH) resulted in requirement of specially designed reactors, which led to high costs of facility and handling. Ionic liquids, and supercritical fluids-assisted lignin depolymerizations had high selectivity, but the high costs of ionic liquids recycling and supercritical fluid facility limited their applications on commercial scale biomass treatment. Metallic catalyzed depolymerization had great advantages because of its high selectivity to certain monomeric compounds and much milder reaction condition than base-catalyzed or acid-catalyzed depolymerizations. It would be a great contribution to lignin conversion if appropriate catalysts were synthesized.

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

Synergistic effect of co-reactant promotes one-step oxidation of cyclohexane into adipic acid catalyzed by manganese porphyrins

2015 ◽  
Vol 93 (7) ◽  
pp. 696-701 ◽  
Author(s):  
Hui Li ◽  
Yuanbin She ◽  
Haiyan Fu ◽  
Meijuan Cao ◽  
Jing Wang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Co Oxidation ◽  
Adipic Acid ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Catalyst Structure ◽  
Manganese Porphyrins ◽  
Co Oxidation Reaction ◽  
One Step ◽  
Acid Catalyzed

The synergistic effect of cyclohexane and cyclohexanone promoted synthesis of adipic acid catalyzed by [MnIIIT(p-Cl)PP]Cl with cyclohexane and cyclohexanone as co-reactants. The results showed that the conversions of cyclohexane and cyclohexanone were significantly enhanced because of the cyclohexanone synergistic effect, and the higher selectivity to adipic acid was obtained with dioxygen as an oxidant. The studies indicated that the co-oxidation of cyclohexane and cyclohexanone was influenced by the initial molar ratio of cyclohexanone and cyclohexane, catalyst structure, catalyst concentrations, and reaction conditions. The preliminary mechanism of the co-oxidation reaction of cyclohexane and cyclohexanone using [MnIIIT(p-Cl)PP]Cl as the catalyst was proposed.

Synthesis and properties of covalently linked di-p-benzihomoporphyrin-BODIPY conjugates

2021 ◽  
pp. A-I
Author(s):  
Rima Sengupta ◽  
Shubham Tiwari ◽  
Mangalampalli Ravikanth
Keyword(s):  
Individual Characteristic ◽  
Electrochemical Studies ◽  
Dft Studies ◽  
Coupling Condition ◽  
Meso Position ◽  
Acid Catalyzed ◽  
Characteristic Features ◽  
Covalently Linked ◽  
Mild Acid ◽  
Spectral And Electrochemical Studies

Two mono meso-functionalized [20]di-[Formula: see text]-benzihomoporphyrins containing [Formula: see text]-formylphenyl and [Formula: see text]-iodophenyl groups at meso-position respectively were synthesized by condensing one equivalent of appropriate tetrapyrrane with one equivalent of [Formula: see text]-formyl benzaldehyde/[Formula: see text]-iodo benzaldehyde in CH2Cl2 under mild acid catalyzed conditions. The meso-formylphenyl and meso-iodophenyl functionalized di-[Formula: see text]-benzihomoporphyrins were used to synthesize two covalently linked di-[Formula: see text]-benzihomoporphyrins-BODIPY conjugates. The meso-formylphenyl-functionalized di-[Formula: see text]-benzihomoporphyrin was converted to corresponding meso-dipyrrolyl substituted di-[Formula: see text]-benzihomoporphyrin by treating with excess pyrrole under acid catalyzed conditions. In the next step, the meso-dipyrrolyl di-[Formula: see text]-benzihomoporphyrin was subjected to oxidation followed by BF2 complexation to afford the directly linked di-[Formula: see text]-benzihomoporphyrin-BODIPY conjugate. The meso-iodophenyl functionalized di-[Formula: see text]-benzihomoporphyrin was coupled with ethynyl-functionalized BODIPY under mild Pd(0) coupling condition to synthesize diphenylethyne-bridged di-[Formula: see text]-benzihomoporphyrin-BODIPY conjugate. The two conjugates were characterized by HR-MS, NMR, absorption, electrochemical, fluorescence and DFT studies. The spectral and electrochemical studies indicated that the two constituents, di-[Formula: see text]-benzihomoporphyrin and BODIPY units in the conjugates interact weakly and retain their individual characteristic features. DFT studies indicated a possibility of charge transfer between di-[Formula: see text]-benzihomoporphyrin and BODIPY units in conjugates.

scholarly journals Biodiesel Production from a Novel Nonedible Feedstock, Soursop (Annona muricata L.) Seed Oil

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2562 ◽  
Author(s):  
Chia-Hung Su ◽  
Hoang Nguyen ◽  
Uyen Pham ◽  
My Nguyen ◽  
Horng-Yi Juan
Keyword(s):  
Reaction Time ◽  
Seed Oil ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Annona Muricata ◽  
Reaction Conditions ◽  
Biodiesel Feedstock ◽  
Acid Catalyzed ◽  
American Society ◽  
Optimal Reaction

This study investigated the optimal reaction conditions for biodiesel production from soursop (Annona muricata) seeds. A high oil yield of 29.6% (w/w) could be obtained from soursop seeds. Oil extracted from soursop seeds was then converted into biodiesel through two-step transesterification process. A highest biodiesel yield of 97.02% was achieved under optimal acid-catalyzed esterification conditions (temperature: 65 °C, 1% H2SO4, reaction time: 90 min, and a methanol:oil molar ratio: 10:1) and optimal alkali-catalyzed transesterification conditions (temperature: 65 °C, reaction time: 30 min, 0.6% NaOH, and a methanol:oil molar ratio: 8:1). The properties of soursop biodiesel were determined and most were found to meet the European standard EN 14214 and American Society for Testing and Materials standard D6751. This study suggests that soursop seed oil is a promising biodiesel feedstock and that soursop biodiesel is a viable alternative to petrodiesel.

scholarly journals Morpholin-2-one Derivatives via Intramolecular Acid-Catalyzed Hydroamination

Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1643-1648 ◽  
Author(s):  
David Knight ◽  
Thomas Wirth ◽  
Abdul Hadi Aldmairi
Keyword(s):  
Amino Acids ◽  
Catalytic Amount ◽  
Practical Method ◽  
Trifluoromethanesulfonic Acid ◽  
Reaction Conditions ◽  
Available N ◽  
Metal Free ◽  
Acid Catalyzed

Substituted morpholin-2-one derivatives were readily obtained in two steps starting from commercially available N-protected amino acids. In a metal-free and practical method, a catalytic amount of trifluoromethanesulfonic acid was sufficient to generate morpholinones under mild reaction conditions in an intramolecular hydroamination reaction in good to excellent yields.

Preliminary Study on the Removal of Hexavalent Chromium in Wastewater with Reduction of Sulfur Dioxide

2013 ◽  
Vol 864-867 ◽  
pp. 1699-1703
Author(s):  
Ji Ming Wu ◽  
Sheng Gao Cheng
Keyword(s):  
Reaction Time ◽  
Sulfur Dioxide ◽  
Hexavalent Chromium ◽  
Reduction Reaction ◽  
High Concentration ◽  
Reaction Conditions ◽  
Ph Values ◽  
Different Temperatures ◽  
Preliminary Study ◽  
High Concentrations

The paper focused on a self-developed methodology through using sulfur dioxide to deal with high concentration of chromium-containing wastewater. It studied the effects of different pH values, different reaction time, different temperatures and different amounts of sulfur with sulfur dioxide reduction reaction on the chromium-containing wastewater. The results showed that: when the reaction conditions were controlled as follows: the pH values ranged from 2 to 4, the reaction temperature was controlled 40~60°C, the amount of sulfur in theoretical was 1.2 times and the reaction time was 40 min, the hexavalent chromium in the high concentrations of chromium-containing wastewater could be effectively removed.

scholarly journals A mannosyl-carrier lipid of bovine adrenal meddulla and rat parotid

1975 ◽  
Vol 146 (3) ◽  
pp. 645-651 ◽  
Author(s):  
D A White ◽  
C J Waechter
Keyword(s):  
Acid Hydrolysis ◽  
Alkaline Hydrolysis ◽  
Deae Cellulose ◽  
Rapid Loss ◽  
Mild Acid Hydrolysis ◽  
Pig Liver ◽  
High Concentrations ◽  
Rat Parotid ◽  
Chloroform Methanol ◽  
Mild Acid

1. The transfer of mannose from GDP-(U-14-C)mannose into endogenous acceptors of bovine adrenal medullla and rat parotid was studied. The rapidly labelled product, a glycolipid, was partially purified and characterized. 2. It was stable to mild alkaline hydrolysis but yielded (14-C)mannose on mild acid hydrolysis. It co-chromatographed with mannosyl phosphoryl dolichol in four t.l.c. systems and on DEAE-cellulose acetate. Addition of dolichol phosphate or a dolichol phosphate-enriched fraction prepared from pig liver stimulated mannolipid synthesis. 3. The formation of mammolipid appeared reversible, since addition of GDP to a system synthesizing the mannolipid caused a rapid loss of label from the mannolipid. UDP-N-acetylglucosamine did not inhibit mannolipid synthesis except at high concentrations (2 mM), even though in the absence of GDP-mannose, N-acetylglucosamine was incorporated into a lipid having the properties of a glycosylated polyprenyl phosphate. 4. Mannose from GDP-mannose was also incorporated into two other acceptors, (2y being insoluble in chloroform-methanol (2:1, v/v) but soluble in choloroform-methanol-water (10:10:3, by vol.) and (ii) protein. These are formed much more slowly than the mannolipid. 5. Exogenous mannolipid served as a mannose donor for acceptors (i) and (ii), and it is suggested that transfer of mannose from GDP-mannose to mannosylated protein occurs via two intermediates, the mannolipid and acceptor (i).

Efficient Copper-Catalyzed Synthesis of Substituted Pyrazoles at Room Temperature

Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2689-2692 ◽  
Author(s):  
Haifeng Wang ◽  
Xiangli Sun ◽  
Shuangling Zhang ◽  
Guanglu Liu ◽  
Chunjie Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Catalytic System ◽  
Efficient Method ◽  
Room Temperature ◽  
Copper Catalyst ◽  
Condensation Reaction ◽  
Reaction Conditions ◽  
Short Reaction Time ◽  
Acid Catalyzed ◽  
Substituted Pyrazoles

An efficient method for the synthesis of pyrazoles through a copper-catalyzed condensation reaction has been developed. The new catalytic system not only maintained a broad substrate scope but was also active under acid-free reaction conditions, overcoming the conventional requirement for an acid-catalyzed system. Furthermore, the copper catalyst enabled this reaction to be performed at room temperature and in a short reaction time.

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