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General procedure: The copper ion-containing quaternary ammonium salts were prepared as follows: A stoichiometric amount of anhydrous CuCl2 was added to the anhydrous ethanol solution of quaternary ammonium salts. The reaction mixture was refluxed for 1 h. Then the solvent was evaporated completely, golden solid was obtained. The solid was recrystallized in anhydrous ethanol before use. Calculation for [HTA]2[CuCl4]: C, 58.84%; N, 3.61%; H, 10.84%; Cu2+, 8.26%. Found: C, 58.63%; N, 3.62%; H, 10.57%, Cu2+, 8.44%. Other catalysts were prepared using the same method (Table S1).
trimethyldecylammonium tetrachloroferrate(III)[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
88%
In ethanol;Heating;
To a hot ethanol solution of FeCl3 (0.25 mol) the solution of a stoichiometric amount of an ammonium salt in hot ethanol was added, the mixture was stirred for 10 -15 min, ethanol was evaporated in a vacuum. The obtained tetrachloroferrates were washed with dry cold ether and dried in a vacuum dessicator over P4O10 for 1 day. The compounds were green or brown solids. Trimethyldecylammonium tetrachloroferrate(III) (1). Yield 88%. mp 49 -51. IR spectrum, nu, cm-1: 2980, 2875, 1120, 1430. Found, %: C 39.8, H 7.6, N 3.3. C13H30NCl4Fe. Calculated, %: C 39.9, H 7.5, N 3.5.
N-decyl-N,N,N-trimethylammonium octanoate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
55%
With potassium hydroxide; In ethanol;
General procedure: In the next step, alkyltrimethylammonium chlorides3a-c as prepared above (0.07 mol) were dissolved in ethanol(20 mL) and weighed precisely. The exact amount ofchloride ions was determined by AgNO3 titration of smallsamples and the required equimolar amounts of carboxylicacids 4a-c were weighted and added. 95% of KOH, requiredfor neutralization, was weighed as solid pellets. Afterall of the added solid KOH dissolved and KCl precipitated(1 hour), the remaining KOH was titrated as anapproximate 0.25 M solution of KOH in ethanol until potentialof glass electrode dropped below -250 mV whichwas previously determined as the potential of the inflectionpoint. Solutions were filtered to separate the filtrate containingthe products from the precipitated KCl. Filtrateswere concentrated under reduced pressure subsequentlyprecipitating more KCl which was filtered to obtain filtrate containing desired alkyltrimethylammonium carboxylates5a-e in quantitative yields. Solutions were dried first underreduced pressure and followed by high vacuum. However,due to increased solubility of KCl in the presence of theproducts up to 3% of KCl remains in the final product asdetermined by AgNO3 titration and TG analysis.
N-decyl-N,N,N-trimethylammonium decanoate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
55%
With potassium hydroxide; In ethanol;
General procedure: In the next step, alkyltrimethylammonium chlorides3a-c as prepared above (0.07 mol) were dissolved in ethanol(20 mL) and weighed precisely. The exact amount ofchloride ions was determined by AgNO3 titration of smallsamples and the required equimolar amounts of carboxylicacids 4a-c were weighted and added. 95% of KOH, requiredfor neutralization, was weighed as solid pellets. Afterall of the added solid KOH dissolved and KCl precipitated(1 hour), the remaining KOH was titrated as anapproximate 0.25 M solution of KOH in ethanol until potentialof glass electrode dropped below -250 mV whichwas previously determined as the potential of the inflectionpoint. Solutions were filtered to separate the filtrate containingthe products from the precipitated KCl. Filtrateswere concentrated under reduced pressure subsequentlyprecipitating more KCl which was filtered to obtain filtrate containing desired alkyltrimethylammonium carboxylates5a-e in quantitative yields. Solutions were dried first underreduced pressure and followed by high vacuum. However,due to increased solubility of KCl in the presence of theproducts up to 3% of KCl remains in the final product asdetermined by AgNO3 titration and TG analysis.
General procedure: In a 200 mL autoclave chloroalkanes 2a-c (0.21 mol,1 eq) were mixed with 33% trimethylamine solution inethanol (1, 100 mL, 2 eq). The mixture was stirred in an oilbath at 80 C for 3 days. Excess 1 and solvents were removedunder reduced pressure. Products were dissolvedin minimal amount of ethanol required (approx. 5 mL)and recrystallized by addition of ethyl acetate (100 mL).The precipitates were filtered and washed with diethylether (50 mL) and subsequently dried under reduced pressureto yield products in 50% average yield. Products 3 arevery hygroscopic which reduces the yield of recrystallizationin open air (3a 26%, 3b 53%, 3c 55%).