Solvation of Ions. V. Rates of SN2 Reactions in Mixtures of Protic and Dipolar Aprotic Solvents

1963 ◽  
Vol 16 (4) ◽  
pp. 585 ◽  
Author(s):  
AJ Parker

The rates of reaction of methyl iodide with chloride ion in some protic-dipolar aprotic solvent mixtures have been measured. The rate-retarding effect of protic solvents at M concentration in dimethylacetamide is in the order p-NO2C6H4OH > C6H5OH > C6H5SH > C6H5CO2H ≈ CH3OH > C6H5NH2 >H2O ≈ D2O. Protic solvents slow the reaction by a general rather than a specific hydrogen bonding interaction with the anion. Both the dipolar aprotic solvent and the protic solvent, as well as the anion, accept hydrogen bonds, and this influences the interaction between protic solvent and anion.


1970 ◽  
Vol 48 (15) ◽  
pp. 2353-2359 ◽  
Author(s):  
R. L. Benoit ◽  
C. Buisson ◽  
G. Choux

Nuclear magnetic resonance and certain conductivity data are reported for solutions of perchloric and fluorosulfuric acids in sulfolane. Additional measurements were made on solutions of disulfuric and hexachloroantimony (V) acids. HSbCl6 is a strong acid in this weakly basic dipolar aprotic solvent. HClO4, HSO3F, and H2S2O7 are incompletely dissociated with K = 10−2.7, 10−3.3, and ~ 10−5, respectively. The acid strength in dilute solution in sulfolane follows the order HClO4 > HSO3F > H2S2O7, which differs from that known in H2SO4 which is a strongly associated polar protic solvent.



1982 ◽  
Vol 35 (3) ◽  
pp. 535 ◽  
Author(s):  
M Rasmussen ◽  
JM Hope

The N3 : N7 : N9 alkylation patterns for reactions of the lithium, sodium, and potassium salts of adenine with various alkylating agents in dimethyl sulfoxide were determined by 1H n.m.r. spectroscopy. Only for the Li+ salt was any significant effect of ionic association noticed. Of the alkylating agents used, only chloromethyl pivalate gave a concentration dependent alkylation pattern. The latter effect was most pronounced with the heterogeneous alkylation conditions of anhydrous Na2CO3/HCONMe2, adenine, and chloromethyl pivalate; here, increasing concentrations changed the main reaction from N7- to N9-alkylation. Solvent effects on the alkylation patterns were also studied. Within the common dipolar aprotic solvent group, (Me2N)3PO, HCONMe2 and Me2SO, effects were small; in protic solvents, particularly formamide, enhanced N3-alkylation was observed.



2014 ◽  
Vol 50 (68) ◽  
pp. 9650-9652 ◽  
Author(s):  
James Sherwood ◽  
Mario De bruyn ◽  
Andri Constantinou ◽  
Laurianne Moity ◽  
C. Rob McElroy ◽  
...  

Dihydrolevoglucosenone (Cyrene) is a bio-based molecule, derived in two simple steps from cellulose, which demonstrates significant promise as a dipolar aprotic solvent.



1985 ◽  
Vol 50 (11) ◽  
pp. 2493-2508 ◽  
Author(s):  
Petr Kyselka ◽  
Zdeněk Havlas ◽  
Ivo Sláma

Solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions has been studied in binary mixtures with dimethyl sulphoxide, dimethylformamide, acetonitrile and water, and in ternary mixtures of the organic solvents with water. The CNDO/2 quantum chemical method was used to calculate the energies of solvation, molecular structures and charge distributions for the complexes acetonitrile...ion (1:1, 2:1, 4:1), dimethyl sulphoxide...ion (1:1), dimethylformamide...ion (1:1), and acetonitrile (dimethyl sulphoxide, dimethylformamide)...ion...water (1:1:1).



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