Triethylamine-water mixtures

One of the Interesting features of these binary solutions, and of many microemulsions, is their tendency to unmix at higher temperature. For example triethylamine-water mixtures unmix into nearly pure triethylamine and nearly pure water at 18.5 C similarly 2-butoxyethanol has a lower critical solution temperature at 49 C. 

Janicot et al. presented the separation of opium alkaloids using sub-critical and supercritical fluid chromatography [20]. Carbon dioxide-meth-anol-triethylamine-water mixtures were used as the mobile phase with packed aminopropyl or bare silica columns. The influence of aminated polar modifiers such as methylamine, ethylamine, and triethylamine was studied. Figure 7.15 shows the separation of six opium alkaloids narcotine, papaverine, thebaine, codeine, cryptopine, and morphine on a Lichrosorb Si-60 column. The method gave comparable results with HPLC. 

These macromonomers were reacted with a halohydrin to yield phenyl glycidyl ether end-groups. Subsequent copolymerization with ethylene oxide or epichloro-hydrin, using the Vanderberg catalyst (triethylamine/water mixture) produced graft copolymers [187]. 

The kinetics of the reaction between bromopropionate and thiosulfate ions have been studied at 10-40 °C in various ethanol-water mixtures.107 Activation parameters were evaluated as a function of ionic strength and dielectric constant of the medium. The medium effect of mixed solvents on the rate constants of the Menshutkin reaction of triethylamine with ethyl iodide has been studied for binary mixtures of cyclohexane with benzene or ethyl acetate,108 and with chlorobenzene or dimethoxyethane.109 Rates were measured over the temperature range 293.1-353.1 K, and activation parameters were determined. 

Conversion of 2 ,4, 6 -trihydroxyacetophenone to the tricarbonate proceeded smoothly in 87% yield on treatment with 3.3 equivalents of methyl chloroformate and triethylamine in THF at 0°C. Treatment of this tricarbonate with 4 equivalents of sodium borohydride in a 1 1 THF/water mixture at 0°C to ambient temperature gave the phenol 1 in 83% yield. 

To a solution of 1 equivalent (eq.) of lH-tetrazole-1-acetic acid and 1 eq. of triethylamine in 20 ml of tetrahydrofuran cooled to -20°C was added 1 eq. of pivaloyl chloride. After thirty-minute stirring of the mixture 20 ml of a chloroform solution containing 1 eq. of and 1 eq. of triethylamine was poured into the solution cooled at -10°C during a period of 30 minutes. The resulting mixed solution was stirred for 30 minutes at the same temperature, for 1 hour in an ice-water mixture and for 3 hours at room temperature. Removal of a solvent from the reaction mixture afforded an oily residue, which was dissolved into 15 ml of 10% sodium bicarbonate aqueous solution. The resulting aqueous layer was adjusted to pH 1.0-2.0 with 10% hydrochloric acid, washed with ether and extracted with ethyl acetate. The extract was washed with water, dried over sodium sulfate and concentrated under reduced pressure leaving a residue which was triturated with ethyl acetate to obtain 3-acetoxymethyl-8-oxo-7-(2-tetrazol-l-acetylamino)-5-thia-l-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid. 

To a solution of the (+)-5-ethyl-l,2,3,6-tetrahydro-pyridine-3-ol in ethanol and triethylamine water, cooled equiv.) was added allyl bromide and the mixture heated at reflux for 12 h. The mixture was evaporated in vacuo and the residue dissolved in chloroform and washed with 5% aqueous K2C03. The chloroform layer was dried (MgS04) and evaporated in vacuo to give the (+)-l-allyl-5-ethyl-l,2,3,6-tetrahydro-pyridin-3-ol. 

The miscibility properties of TA mixtures show interesting patterns as a function of pressure (Schneider, 1966 1973). An increase in pressure can result in an increase in LCST (e.g. triethylamine + water), a maximum in LCST (e.g. 4-methylpiperidine +... 

The product from Step 3 (0.11 mol) was suspended in 500ml of CHjClj containing 17.4 ml triethylamine, the mixture cooled to -70 °C, trifluoromethanesulphonic anhydride (0.12 mol) added, and the reaction stirred 1 hour at ambient temperature. Thereafter, it was washed with 200 ml water and 100 ml ice cold 1M HCl solution. The organic phase was dried, concentrated, purified by chromatography on a silica gel using CH2Cl2/methyl alcohol, 98 2, and the product isolated in 98% yieid, mp = 68-70 °C. 

To a cooled solution of A(-methylbenzenecarboximidoyl chloride [30] (3.1 g, 20 mmol) in dry THF (50 ml) at —78°C is added a 3.5 molar excess of triethylamine. The mixture is stirred (0.5 h) before addition of a solution of cyclohexanone oxime (1.13g, lOmmol). After refluxing (12h), water is added and the mixture is extracted with dichloromethane (3 x 50 ml), the combined extracts are washed with saturated sodium chloride solution, and dried (Na2S04) before removal of the solvent under reduced pressure. Rash... 

The products of hydrolysis of the 1,3-benzodithiolium cation 152 depend upon the experimental conditions. In acetonitrile-water (3 1) or acetone-water (4 1), after I hour, 153 is obtained. In an acetonitrile-water mixture (4 1), after several hours, or in triethylamine-water (1 15), 154 is obtained in excellent yields. - The mechanism probably involves nucleophilic attack of 152 by water and tautomerism of the 2-hydroxy compound 155 with the open-chain derivative 156. Reaction of 156 with another mole of 152 affords 153, which can lose carbon monoxide to give 157. This last can, in turn, react with 152, giving 154. Intermediate 155 has not been isolated but was identified by NMR in the reaction mixture (Scheme 29). ... 

Experimental measurements of heat transfer coefficients are reported for three binary mixtures near their lower consolute points. Two of these, respectively n-pentane and n-decane in solution with supercritical CO2, involve vapor--liquid equilibrium whereas the third, triethylamine--water, involves liquid--liquid equilibrium. Anomalously high heat transfer coefficients were found for the supercritical mixtures at compositions which condense on heating (retrograde condensation). 

Wetzler and coworkers123 employed 4-aminophthalimide (63) and 4-amino-lV-methyl-phthalimide (64) as solvatochromic (and thermochromic) fluorescent probes in solvent mixtures. A bathochromic shift of the emission spectra was found in mixtures of toluene with ethanol and with acetonitrile123 when the more polar solvent was added to toluene, but raising the temperature causes a relative hypsochromic effect. Mixtures of benzene and acetonitrile were studied by Nevecna and coworkers124 for their polarity by means of the probes 46 and 47 and with respect to the correlation of this with the rate constants of the reaction of triethylamine with ethyl iodide. The fluorescence of the ammonium salt of 4-(l-naphthylsulfonate)aniline (84) in dioxane and water mixtures was studied by Hiittenhain and Balzer125. 

The general procedure for such transformations closely follows that previously described, except the reaction is quenched at — 78 °C by rapid addition of triethylamine (7 equivalents) prior to transfer to the diethyl cthcr/water mixture. For the synthesis of nitrogen heterocyeles, the reaction is carried out at 0 25 °C rather than at —78 "C. 

Fortunately, we were able to regioselectively tosylate the primary hydroxyl in 42 with p-toluenesulfonyl chloride, triethylamine, and DMAP in dichloromethane at room temperature over 14 h tosylate 63 was isolated in 85% yield. The subsequent nucleophilic displacement with iodide also proceeded satisfactorily delivering the 6-deoxy-6-iodopyranoside 41 in 92% yield. With the desired 6-iodo sugar successfully prepared, we examined its Vasella reductive ring cleavage with Zn dust (size <10 pm) in a 4 1 THF / water mixture at reflux (Scheme 13). A single product was formed according to TLC analysis. However, our H-NMR examination of this product revealed that it was in fact a 1 1 mixture of the two anomeric hemiacetals 40a and 40P formed in 80% yield. 

A solution of 45 mmols of 1-bromo-3,7,11-trimethyl-2,6,10-dodecatriene (obtained from synthetic farnesol, commercially available and containing four isomers) in 10 ml of benzene was added dropwise at 0°C to a stirred solution of 45 mmols of piperonyipiperazine in 60 ml of benzene containing 5 g of triethylamine. The mixture was stirred for 2 hours and then the precipitated triethylammonium bromide was filtered off. The benzene solution was washed first with water and then with K2CO3 solution and finally dried (K2CO3). Removal of ben-... 

Experiment 14.1 Demonstration of the presence of a miscibility gap with the help of the systems phenolfwater and triethylaminel water. When heated, a heterogeneous mixture of phenol and water will become a homogeneous solution when the upper critical solution temperature (approx. 339 K) is exceeded. However, even at higher temperatures, a heterogeneous mixture of triethylamine and water remains separated, but when cooled with ice to below the lower critical solution temperature (approx. 292 K), it will become a homogeneous solution. The phenol-water mixture, however, continues to consist of two phases after cooling. 

Hexafluoro-2-(4-fluorophenyl)-2-propyl acrylate (la) and hexafluoro-2-(4-fluorophenyl)-2-propyl methacrylate (lb) were prepared by gradually adding a solution of 0.06 mol of acryloyl or methacryloyl chloride, respectively, in 20 ml of tetrahydrofuran (THE), to a cooled solution of 0.04 mol of HFAF in 50 ml of THF containing 0.06 mol of triethylamine. The mixture was stirred for 10-12 h at room temperature it then was poured into 200ml of water, and the new product was extracted with diethyl ether. After the diethyl ether was evaporated, the crude product was purified by column chromatography using a mixture of hexane and dichloromethane (1 1 by volume) as the elution solvent. Distillation afforded la, b.p. 72-74°C/10" mm Hg, and Ib, b.p. 48-52°C/10" mm Hg. 

Derivatization with PITC may alternatively be used to detect primary and secondary amino acids as the phenylthiocarbamoyl (PTC) derivatives (Figure 9) [58-62]. The PITC derivatization reagent, made up fresh each day, consists of ethanol/triethylamine/water/PITC (7 1 1 1 by vol) and is stored at —20 °C under nitrogen to prevent degradation. The derivatization procedure is identical for all dried samples (standard mixtures, hydrolysates, serum and urine extracts). PITC reagent (100 pi) is mixed throughly with the dried sample and allowed to react for 5 min at room temperature. The mixture is evaporated to dryness under vacuum and the... 

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