scholarly journals Effect of relative percentage of acid and base sites on the side-chain alkylation of toluene with methanol

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12703-12709
Author(s):  
Huijun Li ◽  
Bin Wang ◽  
Yueli Wen ◽  
Chunyao Hao ◽  
Yuhua Liu ◽  
...  
Keyword(s):  
Side Chain ◽  
Strong Base ◽  
Relative Percentage ◽  
Acid And Base

For the side chain alkylation of toluene with methanol, middle base sites can improve the selectivity of styrene and ethylbenzene. With enough middle base sites on the catalysts, strong base sites benefit the selectivity of styrene.

scholarly journals An Active Absorbent for Cleanup of High-Concentration Strong Acid and Base Solutions

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3389
Author(s):  
Nara Han ◽  
Sol Park ◽  
Byung Kwon Kaang ◽  
Wooree Jang ◽  
Hye Young Koo ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Strong Acid ◽  
Absorption Capacity ◽  
Dust Particles ◽  
High Concentration ◽  
Strong Base ◽  
Base Solution ◽  
Acid And Base ◽  
Drop Tests ◽  
High Absorption

There is significant interest in developing novel absorbents for hazardous material cleanup. Iron oxide-coated melamine formaldehyde sponge (MFS/IO) absorbents with various IO layer thicknesses were synthesized. Various other absorbents were also synthesized and compared to evaluate the absorption capability of the MFS/IO absorbents for strong acid (15%, v/v) and base (50%, m/m) solutions. Specifically, absorbent and solution drop tests, dust tests, and droplet fragment tests were performed. Among the various absorbents, MFS/IO absorbents possessing a needlelike surface morphology showed several unique characteristics not observed in other absorbents. The MFS/IO absorbents naturally absorbed a strong base solution (absorption time: 0.71–0.5 s, absorption capacity: 10,000–34,000%) without an additional external force and immediately absorbed a strong acid solution (0.31–0.43 s, 9830–10,810%) without absorption delay/overflow during absorbent and solution drop tests, respectively. The MFS/IO absorbents were also demonstrated to be ideal absorbents that generated fewer dust particles (semiclass 1 (ISO 3) level of 280 piece/L) than the level of a clean room (class 100). Furthermore, the MFS/IO absorbents were able to prevent the formation of droplet fragments and solution overflow during the solution drop test due to their unique surface morphology and extremely high absorption speed/capacity, respectively.

Pteridines CX

Pteridines ◽  
1999 ◽  
Vol 10 (3) ◽  
pp. 79-90 ◽  
Author(s):  
Hermann Traub ◽  
Wolfgang Pfleiderer
Keyword(s):  
Functional Groups ◽  
Side Chain ◽  
Amino Group ◽  
Nucleophilic Displacement ◽  
Acid And Base ◽  
Displacement Reactions ◽  
Amide Acetals

Summary A series of new 6-substituted 2,4-diaminopteridines (3-23) and pterins (26-43) have been synthesized by nucleophilic displacement reactions at the side chain of 6-bromomethyl-2,4-diaminopteridine (2) and 6- bromomethylpterin (25) using various types of 0-, N- and S-nucleophiles. Acid and base hydrolyses allow easy conversion of the 2,4-diaminopteridines (3-5, 7, 9, 10, 12, 19-21 and 23) into the corresponding pterins (26-32, 39-42). Acylations take place at the amino as well as at the functional groups in the side chain (44-46). A versatile protection of the amino group in pterins is its transformation into the N ,N -dimethylaminomethylcnimino function by amide-acetals (47, 50) allowing subsequently selective acylations at the side chain (48, 49).

Amphoteric water as acid and base for protic ionic liquids and their electrochemical activity when used as fuel cell electrolytes

2018 ◽  
Vol 206 ◽  
pp. 353-364 ◽  
Author(s):  
Muhammed Shah Miran ◽  
Tomohiro Yasuda ◽  
Ryoichi Tatara ◽  
Md. Abu Bin Hasan Susan ◽  
Masayoshi Watanabe
Keyword(s):  
Ionic Liquids ◽  
Fuel Cell ◽  
Strong Acid ◽  
Trifluoromethanesulfonic Acid ◽  
Electrochemical Activity ◽  
Protic Ionic Liquids ◽  
Strong Base ◽  
Acid And Base ◽  
Cell Electrolytes ◽  
Fuel Cell Electrolytes

Amphoteric water was mixed with equimolar amounts of a super-strong acid, trifluoromethanesulfonic acid (TfOH), and a super-strong base, 1,8-diazabicyclo-[5.4.0]-7-undecene (DBU) to explore the properties as fuel cell electrolytes.

scholarly journals Novel Resins for Efficient Desalination

Substantia ◽  
2021 ◽  
pp. 39-48
Author(s):  
Tanita Gettongsong ◽  
Mojtaba Taseidifar ◽  
Richard M. Pashley ◽  
Barry W. Ninham
Keyword(s):  
Chemical Properties ◽  
Strong Acid ◽  
Electrolyte Solutions ◽  
Strong Base ◽  
Ph Values ◽  
Surface Charging ◽  
Physico Chemical ◽  
Electrical Conductivities ◽  
Acid And Base ◽  
Chemical Cross Linking

This paper reports the synthesis and properties of new polymer resins containing strong acid and base groups for optimising applications in desalination. Several polyampholytic gels were synthesised with a ratio of 1:1 of strong acid (sulphonate) and strong base (quaternary ammonium) groups and a zwitterionic resin with a 1:1 strong acid and base ratio. The physico-chemical properties of these highly charged resins were studied in electrolyte solutions over a range of pH values, in particular: effects of chemical cross-linking, water and electrolyte swelling; bulk electrical conductivities and surface charging properties in different pH values. The results from absorption of NaCl showed that the resins have considerable potential for more effective desalination than other resin-based techniques.

scholarly journals Reaction Mechanism for Direct Proton Transfer from Carbonic Acid to a Strong Base in Aqueous Solution I: Acid and Base Coordinate and Charge Dynamics

2016 ◽  
Vol 120 (9) ◽  
pp. 2271-2280 ◽  
Author(s):  
Snehasis Daschakraborty ◽  
Philip M. Kiefer ◽  
Yifat Miller ◽  
Yair Motro ◽  
Dina Pines ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Reaction Mechanism ◽  
Proton Transfer ◽  
Carbonic Acid ◽  
Strong Base ◽  
Charge Dynamics ◽  
Acid And Base

scholarly journals Natural Plant Extracts as Acid-Base Indicator and Determination of Their pKa Value

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
N. Kapilraj ◽  
S. Keerthanan ◽  
M. Sithambaresan
Keyword(s):  
Extraction Procedure ◽  
Colour Change ◽  
Cost Effective ◽  
Strong Acid ◽  
Weak Acid ◽  
Acid Base ◽  
Strong Base ◽  
Brownish Yellow ◽  
Acid And Base ◽  
Acids And Bases

Commonly used indicators for acid-base titrations are synthetic, and this work was focused to identify the eco-friendly natural indicators and to determine their pKa values. The analytical potential of the flower extracts is very promising as seen in its application in acid-base titrimetry. These selected flower extracts were found to perform well in titrating strong acid-strong base than in weak acid-strong base. We have obtained a sharp and clear colour change from red to brownish yellow for the Bougainvillea glabra extract, from red to yellow for the Bauhinia purpurea extract, and from red to brownish yellow for the Impatiens balsamina extract. All the three flower extracts gave clear colour change with acids and bases, and the colour change was maintained with different acids and bases. The sharp contrast between their colours in acid and base made the pigment suitable for use as acid-base indicators. As these flower extracts have very simple,cost-effective, environment friendly extraction procedure and excellent performance with sharp colour change in end points of the titrations, it would be possible to replace the standard indicators being used in conventional laboratories with natural flower indicators.

scholarly journals Structural features of selected protic ionic liquids based on a super-strong base

2019 ◽  
Vol 21 (45) ◽  
pp. 25369-25378
Author(s):  
Alessandro Triolo ◽  
Fabrizio Lo Celso ◽  
Carlo Ottaviani ◽  
Pengju Ji ◽  
Giovanni Battista Appetecchi ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Md Simulation ◽  
Structural Features ◽  
Simulation Studies ◽  
Protic Ionic Liquids ◽  
Strong Base ◽  
X Ray ◽  
X Ray Scattering ◽  
Acid And Base ◽  
Ray Scattering

X-ray scattering and MD simulation studies of Protic ionic liquids formed by superstrong acid and base combination.

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