Solvents, acidic ethanolamines

Organic acids, ethanolamine, dimethyl sulfoxide, etc. were also used as solvents for different extraction techniques. 

Titanium, D. of as oxide, via tannic acid and phenazone complexes, (g) 470 by hydrogen peroxide, (s) 696 Titan yellow 692 Titrand 257 Titrant 257 Titration 257 classification of, 258 in an inert atmosphere, 376, 629 in non-aqueous solvents, 281 aniline (and ethanolamine), D. of, 307 indicators for, 283 solvents for, 283... 

Recently, an environmentally benign and volume efficient process for enzymatic production of alkanolamides has been described where CALB catalyzes the amidation of lauric acid and ethanolamine in the absence of solvent, at 90 °C, to keep the reactants in a liquid state and to remove the water [18]. The enzyme was both very active and stable under the reaction conditions, with about half of the activity remaining after two weeks, obtaining the final amide with a 95% yield (Scheme 7.6). 

Fig. 2.12 Relationship between the ion association constants (log KA) and the reciprocal of solvent permittivity (1 /er) (solid line) and between the degree of ion association (a) and log (c/(A) (dotted curve), (open circles Bu4NPic in AN, NB, MeOH, Ac, Py, DCE, o-dichlorobenzene, acetic acid, chlorobenzene and benzene closed squares KCI in ethanolamine, MeOH, EtOH, acetic acid and H20-dioxane mix-tures). The solid line was obtained using a Eq. (2.19) for 0 = 0.6 nm.

Esters are prepared by reaction of aldonic acids or lactones with an alcohol in the presence of hydrogen chloride 80 the reaction is slower with 1,4-lactones. Amides are readily formed from lactones by reaction with liquid ammonia followed by evaporation of the solvent.81 D-Gluconamide has also been prepared by treatment of D-glucono-1,5-lactone with concentrated ammonium hydroxide and subsequent precipitation with ethanol.82 A-Substituted aldonamides may be obtained by reaction of the aldono-lactones with ethanolamine, diethanolamine, and related species.83... 

However, for certain applications non-aqueous solvents have their advantages. Uni-univalent electrolytes dissolved at low to moderate concentrations in solvents with a relative permittivity larger than, approximately, 30 are completely dissociated into ions. Of the solvents on the List, methanol, glycols, glycerol, formic acid, ethylene and propylene carbonate, 4-butyrolactone, ethanolamine, 2-cyanopyridine, acetonitrile, nitromethane and -benzene, the amides, whether N-substituted or not, dimethyl sulfoxide, sulfolane, dimethyl sulfate, and hexamethyl phosphoramide have s > 30 at ambient conditions (Table 3.5). Most of these solvents have, indeed, been used in electrochemical processes. 

Essentially, all primary skin irritants include acids, alkalis, metals, salts, and solvents. Among organic acids one may include acetic acid, acrylic acid, carbolic acid, chloroacetic acid, formic acid, lactic acid, oxalic acid, and salicylic acid. Among inorganic acids one may list arsenious acid, chromic acid, hydrochloric acid, hydrofluoric acid, nitric acid, phosphoric acid, and sulfuric acid. Alkalis include butylamines, ethylamines, ethanolamines, methylamines, propylamines, and triethanolamine. One also may include ammonium carbonate, ammonium hydroxide, calcium carbonate, calcium cyanamide, calcium hydroxide, calcium oxide, potassium carbonate, potassium hydroxide, sodium carbonate (soda ash), sodium hydroxide (caustic soda), and sodium silicate. 

As described earlier, the total cellular lipids can be recovered by use of a neutral organic solvent system, such as chloroform-methanol-water. Silicic acid column chromatography, thin-layer chromatography, and high-pressure liquid chromatography (HPLC) are well suited to isolation of the ethanolamine-rich phospholipids. Only column and thin-layer chromatographic purification will be discussed at this juncture. 

Ethylenediamine (en), NH2C2H4NH2, a strongly basic substance, may be considered to represent solvents that are weakly acidic compared with water. Ethylenediamine is therefore useful as a solvent for the titration of weakly acidic substances. It is a leveling solvent for adds whose ionization constants are larger than about 10 in water thus acetic add and hydrochloric acid are leveled to about equal strength. The titrant base normally used in en is sodium ethanolamine. The autoprotolysis constant of en is 5 x 10" for the equilibrium... 

Amphiprotic protogenic solvents have higher acidic properties, but lower basic ones (always in comparison to water). Examples are formic and acetic acid. Amphiprotic protophilic solvents have lower acidity and higher basicity than water, with formamide or ethanolamine as examples. Aprotic dipolar solvents have low acidity and (occasionally) basicity as well, with A,A-dimethylformamide and dimethylsulfoxide as examples for protophilic dipolar solvents and acetonitrile for a protophobic dipolar solvent. 

Cobalamin analogs inhibit ethanolamine deaminase. (Ethanolamine is an industrial solvent that selectively absorbs the acid gases COj and H2S.)... 

Bush and Helman (I6) determined primidone in urine and blood as phenobarbital, after oxidation of the former vdth dichromate. Primidone auid any phenobarbital in the samples were extracted with ether. The ether extracts were extracted with 0,1 M ethanolamine to remove phenobarbital, and then evaporated to dryness. The residue was treated with 0,0l 2 M potassium dichromate in 9.5 M sulfuric acid to oxidize primidone to phenobarbital. The phenobarbital formed was extracted into ether, and the ether washed with pH 6,2 buffer, 0,1 N hydrochloric acid, and water. Finally, the phenobarbital formed was extracted into 0.1 M ethanolamine and determined from its ultraviolet absorption at pH 9,3, 7,3, and 5 3. Partition coefficients for primidone in several solvent systems were also determined,... 

A basic solvent, such as ethanolamine, will level many acids by converting them to the solvent cation HOC2H4NH and will differentiate many bases. 

In addition to the equipment properties and selected operating conditions, the process performance depends to a large extent on the state of the active solvent component(s). Commonly nsed solvents include physical solvents like methanol (Rectisol) and the dimethyl ethers of polyethylene glycol (Selexol), chemical solvents like aqneous solutions of carbonates such as K2CO3 and Na2C03, of amino acid salts such as mixtures of potassium hydroxide and alanine or tanrine, and especially of alkanolamines such as mono-ethanolamine (MEA), di-ethanolamine (DEA), (activate) methyl-di-ethanolamine (MDEA), di-isopropanolamine (DIPA), di-glycolamine (DGA), 2-amino-2-methyl-l-propanol (AMP), and piperazine (PZ) (1). 

---