scholarly journals Ring-opening hydrolysis of spiro-epoxyoxindoles using a reusable sulfonic acid functionalized nitrogen rich carbon catalyst

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12808-12814
Author(s):  
Parth Patel ◽  
Raj Kumar Tak ◽  
Bhavesh Parmar ◽  
Shilpa Dabas ◽  
Brijesh Patel ◽  
...  
Keyword(s):  
Ring Opening ◽  
Sulfonic Acid ◽  
Catalytic Synthesis ◽  
Carbon Catalyst ◽  
Vicinal Diols ◽  
Hydrolysis Of

Catalytic synthesis of vicinal diols via ring-opening hydrolysis of spiro-epoxyoxindoles.

scholarly journals Pretreatment of Switchgrass for Production of Glucose via Sulfonic Acid-Impregnated Activated Carbon

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 504
Author(s):  
Yane Ansanay ◽  
Praveen Kolar ◽  
Ratna Sharma-Shivappa ◽  
Jay Cheng ◽  
Consuelo Arellano
Keyword(s):  
Activated Carbon ◽  
Sulfonic Acid ◽  
Solid Acid ◽  
Methanesulfonic Acid ◽  
Biofuel Production ◽  
Acid Catalysts ◽  
Effects Of Temperature ◽  
Carbon Catalysts ◽  
Hydrolysis Of

In the present research, activated carbon-supported sulfonic acid catalysts were synthesized and tested as pretreatment agents for the conversion of switchgrass into glucose. The catalysts were synthesized by reacting sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid with activated carbon. The characterization of catalysts suggested an increase in surface acidities, while surface area and pore volumes decreased because of sulfonation. Batch experiments were performed in 125 mL serum bottles to investigate the effects of temperature (30, 60, and 90 °C), reaction time (90 and 120 min) on the yields of glucose. Enzymatic hydrolysis of pretreated switchgrass using Ctec2 yielded up to 57.13% glucose. Durability tests indicated that sulfonic solid-impregnated carbon catalysts were able to maintain activity even after three cycles. From the results obtained, the solid acid catalysts appear to serve as effective pretreatment agents and can potentially reduce the use of conventional liquid acids and bases in biomass-into-biofuel production.

Acid–base synergistic catalysis of biochar sulfonic acid bearing polyamide for microwave-assisted hydrolysis of cellulose in water

Cellulose ◽  
2018 ◽  
Vol 26 (2) ◽  
pp. 751-762 ◽  
Author(s):  
Zengtian Chen ◽  
Qingfeng Li ◽  
Yuxue Xiao ◽  
Chao Zhang ◽  
Zaihui Fu ◽  
...  
Keyword(s):  
Sulfonic Acid ◽  
Acid Base ◽  
Synergistic Catalysis ◽  
Microwave Assisted ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

scholarly journals Novel Greener Microwave-Assisted Deprotection Methodology for the 1,3-Dioxolane Ketal of Isatin Using Calix[n]arenes

2022 ◽  
Author(s):  
Lucas Barbosa ◽  
Tiago da Silva ◽  
Michelle Rezende ◽  
Bianca da Silva ◽  
Rodrigo Guzzo ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Sulfonic Acid ◽  
Microwave Energy ◽  
Protecting Group ◽  
Additional Advantage ◽  
Microwave Assisted ◽  
Combined Use ◽  
Ketone Carbonyl ◽  
First Time ◽  
Hydrolysis Of

In this work, the combined use of p-sulfonic acid-calix[n]arene and microwave energy to hydrolyze the 1,3-dioxolane ketal of isatin was evaluated with excellent results. This is the first time that p-sulfonic acid-calix[n]arene has been used as the catalyst in a ketal hydrolysis reaction and the deprotection of the ketone carbonyl of isatin is reported. The presence of 2.5 mol% of p-sulfonic acid-calix[4,6]arene at 160 ºC resulted in over 96% conversion of this ketal in 10 min, with the additional advantage of using water as a solvent. This catalytic system (aqueous phase containing p-sulfonic acid-calix[4]arene) was reused for five consecutive cycles, with a conversion above 96% maintained. This reusable system is not practicable using p-toluenesulfonic acid and p-hydroxybenzenesulfonic acid as catalysts since both are extracted to the organic phase with the reaction product. The hydrolysis of 1,3-dioxolane ketal of isatins with different substituents (CH3, I, Br, Cl, F, NO2) in the aromatic ring was also evaluated. The protecting group of 5-methyl-isatin was removed with 73% conversion using 2.5 mol% of p-sulfonic acid-calix[4]arene at 160 ºC for 5 min. In contrast, the ketal of 5-nitro-isatin reached 80% conversion using the same conditions after 40 min.

Superhydrophobic functionalization of cutinase activated poly(lactic acid) surfaces

2017 ◽  
Vol 19 (3) ◽  
pp. 816-822 ◽  
Author(s):  
A. Ortner ◽  
A. Pellis ◽  
C. Gamerith ◽  
A. Orcal Yebra ◽  
D. Scaini ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Enzymatic Hydrolysis ◽  
Ring Opening ◽  
Superhydrophobic Surfaces ◽  
Poly Lactic Acid ◽  
Hydrolysis Of

Controlled enzymatic hydrolysis of PLA surfaces, followed by ring opening of AKD, leads to superhydrophobic surfaces (WCA >150°).

Hydrolysis of Sulfonic Acid Esters

2008 ◽  
pp. 1
Author(s):  
J. Drabowicz ◽  
P. Kiełbasiński ◽  
P. Łyżwa ◽  
A. Zając ◽  
M. Mikołajczyk
Keyword(s):  
Sulfonic Acid ◽  
Hydrolysis Of ◽  
Acid Esters

scholarly journals The acidic hydrolysis of N-acetylneuraminic 4,5-oxazoline allows a direct functionalization of the C5 position of Neu5Ac2en (DANA)

RSC Advances ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 162-165 ◽  
Author(s):  
Paola Rota ◽  
Paolo La Rocca ◽  
Federica Cirillo ◽  
Marco Piccoli ◽  
Pietro Allevi ◽  
...  
Keyword(s):  
Ring Opening ◽  
Antiviral Drugs ◽  
Amino Group ◽  
Group Key ◽  
Acidic Hydrolysis ◽  
Direct Functionalization ◽  
Direct Generation ◽  
Hydrolysis Of

The Neu5Ac 4,5-oxazoline ring-opening allows the direct generation of a free C5-amino group key to synthesize antiviral drugs.

Arene chromium complexes with functionalized anellated rings. Selective formation of highly substituted polycycles

2002 ◽  
Vol 74 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Holger Butenschön
Keyword(s):  
Good Yield ◽  
Ring Opening ◽  
Ring Expansion ◽  
Chromium Complexes ◽  
Ketone Group ◽  
Aldol Additions ◽  
Cope Rearrangements ◽  
Hydrolysis Of ◽  
Selective Formation ◽  
Tricarbonylchromium Complexes

Tricarbonylchromium complexes of benzocyclobutenone, benzocyclobutenedione, and 1,3-indandione are readily prepared by hydrolysis of the complexes of the corresponding acetals. Reduction of the benzocyclobutenone complex gives rise to an oxy-anion-driven ring opening to the corresponding ortho-quinodimethane intermediate, which can be trapped with dienophiles. Addition of 1-ethoxy-1-lithioethene allows a stereoselective ring expansion followed by an anionic ketol rearrangement with complete diastereoselectivity. Addition of 1-lithio-1-methoxyallene gives rise to a rare anionic 1-vinylcyclobutenol-cyclohexadienol rearrangement. Diaddition of alkenylmetal reagents at both keto groups in benzoyclobutenedione complexes causes dianionic oxy-Cope rearrangements to occur at ­78 °C, which are followed by diastereoselective intramolecular aldol additions. In some cases, a completely regioselective mono hydrolysis of di(enolates) was observed. Dianionic oxy-Cope rearrangements can also be realized with unstrained benzil derivatives giving 1,6-hexanediones and the corresponding aldol adducts. The 1,2,3-indantrione complex is obtained by oxidation of the 1,3-indandione complex with dimethyldioxirane in good yield and reacts with its central ketone group in hetero Diels­Alder cycloadditions.

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