Quaternary Nitrogen Heterocycles. IV. The 1-Methyl-4-nitroquinolinium and 4,4-Diiodo-1,1-dimethy1-1,4-dihydroquinolinium Cations, Two Methylation Products of 4-Nitroquinoline and their Reactions in Aqueous Solutions

1974 ◽  
Vol 52 (6) ◽  
pp. 951-961 ◽  
Author(s):  
John W. Bunting ◽  
William G. Meathrel
Keyword(s):  
Aqueous Solution ◽  
Methyl Iodide ◽  
Alkaline Solution ◽  
Silver Iodide ◽  
Spectroscopic Data ◽  
Nitrogen Heterocycles ◽  
Aqueous Alkaline Solution ◽  
Quaternary Nitrogen ◽  
Unexpected Product ◽  
Species Being

Methylation of 4-nitroquinoline with methyl fluorosulfonate ("magic methyl") gives the expected 1-methyl-4-nitroquinolinium fluorosulfonate. However, methylation with methyl iodide gives an unexpected product (C11H12I3N) which is shown to be 4,4-diiodo-1,1-dimethyl-1,4-dihydroquinolinium iodide. This latter salt readily loses a molecule of methyl iodide in aqueous alkaline solution and forms 4-hydroxy-4-iodo-1-methyl-1,4-dihydroquinoline. This latter product reacts in aqueous solution with excess silver iodide or bromide in the presence of silver nitrate to give 3-iodo-1-methyl-4-quinolone or the corresponding 3-bromo derivative. The 1-methyl-4-nitroquinolinium cation readily forms a pseudobase in aqueous solution (pKROH = 5.31; pKRO− = 10.95 ). Kinetic and spectroscopic data are consistent with the predominant neutral pseudobase species being 4-hydroxy-1-methyl-4-nitro-1,4-dihydroquinoline, while the predominant pseudobase anion is the alkoxide ion of 2-hydroxy-1-methyl-4-nitro-1,2-dihydroquinoline.

Regioselective Arylation of 1,3-Dimethyllumazine and Its 5-Oxide by Diazonium Salts

Pteridines ◽  
1997 ◽  
Vol 8 (3) ◽  
pp. 188-194 ◽  
Author(s):  
Takashi Sugimoto ◽  
Chihiro Seo ◽  
Shizuaki Murata ◽  
Wolfgang Pfleiderer
Keyword(s):  
Aqueous Solution ◽  
Molecular Orbital ◽  
Alkaline Solution ◽  
Diazonium Salt ◽  
New Method ◽  
Diazonium Salts ◽  
Molecular Orbital Calculations ◽  
Aqueous Alkaline Solution ◽  
Aryl Group ◽  
Benzene Diazonium

Summary A new method to introduce an aryl group directly into the pteridine nucleus by the action of arene diazonium salt in an aqueous alkaline solution is described. 1,3-Dimethyllumazine and benzene diazonium chloride reacts in an aqueous solution at pH 8-9 to give 7 -phenyl-1 ,3-dimethyllumazine together with a little of 6-phenyi-1 ,3-dimethyllumazine. The analogous reactions of 1,3-dimethyllumazine with 4-methyl-, 4-methm.),-, 4-chloro-, and 3-chlorobenzene diazonium chlorides give the corresponding 7-aryl-1,3-dimethyllumazines as major products together with a little of 6-aryl-1,3-dimethyllumazines. Reactions of 1,3-dimethyllumazine 5-oxide with arene diazonium salts under the same conditions exclusively afford the corresponding 6-aryl-1,3-dimethyllumazine 5-oxides which are easily converted to 6-aryl-1,3-dimethyllumazine by the action of tributylphosphine. Mechanisms concerning regioselectivities are investigated by using molecular orbital calculations.

Quaternary Nitrogen Heterocycles. V. Substituent Effects on the Equilibrium Constants for Pseudobase Formation from Quinolinium and Isoquinolinium Cations

1974 ◽  
Vol 52 (6) ◽  
pp. 962-974 ◽  
Author(s):  
John W. Bunting ◽  
William G. Meathrel
Keyword(s):  
Aqueous Solution ◽  
Magnetic Resonance ◽  
Spectral Data ◽  
Proton Magnetic Resonance ◽  
Equilibrium Constants ◽  
Nitrogen Heterocycles ◽  
Substituent Effects ◽  
Stopped Flow ◽  
Substituent Constant ◽  
Quaternary Nitrogen

Equilibrium constants (pKROH) have been measured for pseudobase formation from the 1-methyl-x-nitroquinolinium cations (x = 5–8), the N,N′-dimethyl-1,5-, -1,6-, and -2,7-naphthyridinium dications and various N-substituted quinolinium, isoquinolinium, 5-nitroisoquinolinium, and 1,8-naphthyridinium cations. The pKROH values for N-substituted 5-nitroisoquinolinium and 1,8-naphthyridinium cations are correlated by the equations pKROH = −3.7σ* + 11.6 and pKROH = −4.9σ* + 12.5, respectively (σ* is Taft's substituent constant for the substituent on nitrogen).Proton magnetic resonance and u.v. spectral data have been used to assign the structures of the pseudobases formed from each of the above cations. In several cases ylide formation rather than pseudobase formation has been observed. The N,N′-dimethylnaphthyridinium dications are shown to form zwitterionic alkoxide ions in strongly basic aqueous solution, rather than undergoing attack by a second hydroxide ion.Equilibration between cation and pseudobase occurs at rates near or beyond the limit of the stopped-flow technique for all the above cations, except the 2-cyanomethyl-5-nitroisoquinolinium cation. An analysis of the pH-rate profiles for reversible pseudobase formation from this latter cation is given.

Enhanced Thermal Stability of Esterified Lignin in Different Solvent Mediums

2018 ◽  
Vol 9 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Sharifah Nurul Ain Syed Hashim ◽  
Sarani Zakaria ◽  
Chin Hua Chia ◽  
Sharifah Nabihah Syed Jaafar
Keyword(s):  
Thermal Stability ◽  
Alkaline Solution ◽  
Room Temperature ◽  
Hydroxyl Groups ◽  
Aqueous Alkaline Solution ◽  
Alkali Lignin ◽  
Weight Percentage ◽  
H Nmr ◽  
Ft Ir ◽  
Thermal Stability Of

In this study, soda alkali lignin from oil palm empty fruit bunch (EFB-AL) and kenaf core (KC-AL) are esterified with maleic anhydride under two different conditions, namely i) pyridine at temperature of 120°C for 3h and ii) aqueous alkaline solution at room temperature for 4h. As a result, the weight percentage gain (WPG) of the esterified EFB-AL (EFB-EL) and esterified KC-AL (KC-EL) in pyridine demonstrated a higher compared to aqueous alkaline solution. The FT-IR results of EFB-EL and KC-EL in both solvents exhibited some changes at the carbonyl and hydroxyl groups. Furthermore, the esterification process induced the carboxylic peak to appear in both alkali lignin samples. The outcome is confirmed by conducting H-NMR analysis, which demonstrated ester and carboxylic acid peaks within the spectral analysis. Finally, the TGA results showed both EFB-EL and KC-EL that are exposed to aqueous alkaline actually possessed better thermal stability and higher activation energy (Ea) compared to the esterified samples in pyridine.

Dissolution of spent nuclear fuel fragments at high alkaline conditions under H2 overpressure

MRS Advances ◽  
2016 ◽  
Vol 1 (62) ◽  
pp. 4163-4168
Author(s):  
E. González-Robles ◽  
M. Herm ◽  
V. Montoya ◽  
N. Müller ◽  
B. Kienzler ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Partial Pressure ◽  
Nuclear Fuel ◽  
Alkaline Solution ◽  
Spent Nuclear Fuel ◽  
Dissolution Tests ◽  
The Matrix ◽  
Alkaline Conditions ◽  
Long Term Behavior

ABSTRACTThe long-term behavior of the UO2 fuel matrix under conditions of the Belgian “Supercontainer design” was investigated by dissolution tests of high burn-up spent nuclear fuel (SNF) in high alkaline solution under 40 bar of (Ar + 8%H2) atmosphere. Four fragments of SNF, obtained from a pellet previously leached during two years, were exposed to young cement water with Ca (YCWCa) under 3.2 bar H2 partial pressure in four single/independent autoclave experiments for a period of 59, 182, 252 and 341 days, respectively. After a decrease of the concentration of dissolved 238U, which is associated with a reduction of U(VI) to U(IV), the concentration of 238U in solution is constant in the experiments running for 252 and 341 days. These observations indicate an inhibition of the matrix dissolution due to the presence of H2. A slight increase in the concentration of 90Sr and 137Cs in the aqueous solution indicates that there is still dissolution of the grain boundaries. These findings are similar to those reported for spent nuclear fuel corrosion in synthetic near neutral pH solutions.

Acid-Base Equilibrium of 5-Methoxy-6-methyluracil in Solutions: Evaluation of Content of Anionic Forms in Aqueous Alkaline Solution

2018 ◽  
Vol 88 (6) ◽  
pp. 1076-1080 ◽  
Author(s):  
S. F. Petrova ◽  
T. R. Nugumanov ◽  
L. V. Spirikhin ◽  
Yu. I. Murinov ◽  
S. P. Ivanov
Keyword(s):  
Alkaline Solution ◽  
Aqueous Alkaline Solution ◽  
Acid Base ◽  
Base Equilibrium ◽  
Acid Base Equilibrium

Characterization of Metakaolin-Based Materials for Dye Adsorption from Aqueous Solution

2018 ◽  
Vol 283 ◽  
pp. 88-94
Author(s):  
Narumon Lertcumfu ◽  
Pharatree Jaita ◽  
Gobwute Rujijanagul ◽  
Tawee Tunkasiri
Keyword(s):  
Aqueous Solution ◽  
Aluminum Oxide ◽  
Distribution Coefficient ◽  
Alkaline Solution ◽  
Dye Adsorption ◽  
Adsorption Properties ◽  
High Adsorption ◽  
Uptake Capacity ◽  
High Adsorption Capacity

The properties of metakaolin-based materials were investigated. The studied materials were prepared by mixing metakaolin and aluminum oxide in alkaline solution. The obtained samples were cast into plastic molds and then left at 27°C for 24 h. The properties of the materials were investigated using XRD, FTIR, and SEM. The obtained results suggested that reaction of the mixed materials occurred. The adsorption properties of the materials, including removal efficiency, distribution coefficient, and uptake capacity were determined. The obtained results revealed that the studied materials exhibited high adsorption capacity, which is good for the adsorbent applications.

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