Preparation of sulfonated polyorganosiloxanes and their acid catalysis

Suzuki, Sohei; Tohmori, K.; Ono, Yoshio

doi:10.1016/0304-5102(87)87020-7

Cited by 24 publications

(8 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Despite the disappointing failure of such heterocyclic substrates, the present solid acid-catalyzed flow nitration through a catalyst-packed bed reactor exhibited wide substrate tolerance with respect to both liquid and solid aromatic substrates. 47…”

Section: Acs Sustainablementioning

confidence: 99%

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO₃ on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

Ishitani

Sasaya

Kobayashi

2023

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Continuous-flow nitration of aromatic compounds catalyzed by a well-optimized solid acid catalyst with aqueous nitric acid under liquid phase was investigated. Using a suitable packed bed reactor system furnishing precolumn, the desired flow reaction proceeded to afford a nitroarene in a good yield by adopting Mo(VI)-supported TiO2–ZrO2 mixed-metal oxide. Further investigations toward enhancement on catalytic performance at higher weight hourly space velocity (WHSV) indicated that the mixed-metal oxide prepared by sol–gel method with calcination at 700 °C presented higher performances at 4.0 h–1 WHSV, and more than 90% yield was achieved. The turnover of the catalyst in long-term operation studies revealed that 87% yield was maintained when ca. 43-fold amount of toluene was delivered to the catalyst (g/g). A wide variety of aromatic compounds including both liquid and solid substances were enabled to convert into the corresponding nitroarene compounds by utilizing the developed system.

show abstract

Section: Acs Sustainablementioning

confidence: 99%

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO₃ on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

Ishitani

Sasaya

Kobayashi

2023

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…Over the recent years, numerous publications were dedicated to nitration processes using heterogeneous catalysts, such as gas-solid (gas phase nitration) and liquid-solid (liquid phase nitration) systems [1,4,5]. Nitric acid [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], nitrogen dioxide [25][26][27][28] and nitrates decomposed by acid catalysis [29,30] were all used as nitrating agents. Where the process was based on a liquid-solid process (liquid phase heterogeneous catalytic nitration), where nitric acid was used as the nitrating agent, the main disadvantage was found to be the necessity to use an additional process for separation, or binding of the water resulting from the nitration.…”

Section: Introductionmentioning

confidence: 99%

In search of efficient catalysts and appropriate reaction conditions for gas phase nitration of benzene

Vedyagin¹,

Koskin²,

Mishakov³

2016

REFFIT

View full text Add to dashboard Cite

The present paper is dedicated to the development of a method for the nitrobenzene production using solid acid catalysts, as an alternative to industrial nitration, based on a mixture of concentrated acids. The influence of key parameters of the nitration process (temperature, reagent flow rate, nitrating agent concentration etc.) on the conversion of the initial substrate, the degree of decomposition of nitric acid and the quantity ofresulting oxygenates was studied. Recommendations for the selection of effective catalytic systems (high content of Brønsted acid sites with Ho < −4, high specific surface and resistance to HNO3) were developed and the best conditions for process reactions (temperature 200 °C, aqueous solution of nitric acid with concentration of 30 wt%, “nitric acid:benzene” ratio = 0.76) were found. A method for regeneration of the catalytic activity without unloading the catalyst was proposed. As an example, MoO3/SiO2 sample was tested in a dual-mode nitration/regeneration process, which allowed us to increase the flow rates of reagents and obtain catalyst efficiency of up to STY = 4.09 g/(gcat · h). Several of the most promising catalysts (MoO3/SiO2, WO3/ZrO2 and Nafion/support composite) for the process were tested in identical conditions.

show abstract

“…To overcome these problems, new methods employing solid-acid catalysts have been extensively studied. Silica gel, sulfonated polyoranesiloxanes, acid resins, modified clays, sulfated zirconia, supported sulfuric and sulfonic acids, and zeolites are some of solid-acid catalysts investigated.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on the Nitration of Methane by Acyl Nitrate Catalyzed by H-ZSM5 Zeolite

Silva

Nascimento

2008

J. Phys. Chem. A

View full text Add to dashboard Cite

A theoretical study on the nitration of methane by acyl nitrate catalyzed by HZSM-5 zeolite is reported. The zeolite was represented by a "double ring" 20T cluster. The calculations were performed at the DFT/X3LYP/6-31G** and MP2/6-31G** levels. The first step of the mechanism involves the protonation of the acyl nitrate by the zeolite and the formation of a nitronium-like ion. The reaction proceeds through a concerted step with the attack of the methane molecule by the nitronium-like ion and the simultaneous transfer of a proton from the methane molecule to the zeolite, thus reconstructing the acidic site. The activation energies for the first and second steps of this reaction are, respectively, 14.09 and 10.14 kcal/mol at X3LYP/6-31G** level and 16.68 and 13.85 kcal/mol at the MP2/6-31G**.

show abstract

Preparation of sulfonated polyorganosiloxanes and their acid catalysis

Cited by 24 publications

References 20 publications

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO₃ on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO₃ on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

In search of efficient catalysts and appropriate reaction conditions for gas phase nitration of benzene

Theoretical Study on the Nitration of Methane by Acyl Nitrate Catalyzed by H-ZSM5 Zeolite

Contact Info

Product

Resources

About

Preparation of sulfonated polyorganosiloxanes and their acid catalysis

Cited by 24 publications

References 20 publications

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO3 on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO3 on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

In search of efficient catalysts and appropriate reaction conditions for gas phase nitration of benzene

Theoretical Study on the Nitration of Methane by Acyl Nitrate Catalyzed by H-ZSM5 Zeolite

Contact Info

Product

Resources

About

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO₃ on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts

Liquid-phase Catalytic Continuous-Flow Aromatic Nitration Reactions with Conc. HNO₃ on Modified Mixed-Metal Oxide Composites as High-Yielding Solid Acid Catalysts