Diethylamine. solubility

White orthorhombic crystals density 0.67 g/cm decomposes in moist air melts at 268°C decomposes at 380°C reacts with water dissolves in ether, tetrahydrofuran, and diethylamine solubility in ether, 25g/L at 25°C. 

Like alcohols, amines with fewer than five carbon atoms are generally water-soluble. Also like alcohols, primary and secondary amines form hydrogen bonds and are highly associated. As a result, amines have higher boiling points than alkanes of similar molecular weight. Diethylamine (MW = 73 amu) boils at 56.3 °C, for instance, while pentane (MW = 72 amu) boils at 36.1 °C. 

Whilst some organic compounds can be investigated in aqueous solution, it is frequently necessary to add an organic solvent to improve the solubility suitable water-miscible solvents include ethanol, methanol, ethane-1,2-diol, dioxan, acetonitrile and acetic (ethanoic) acid. In some cases a purely organic solvent must be used and anhydrous materials such as acetic acid, formamide and diethylamine have been employed suitable supporting electrolytes in these solvents include lithium perchlorate and tetra-alkylammonium salts R4NX (R = ethyl or butyl X = iodide or perchlorate). 

FIGURE 3 2 Solvent extraction efficiencies (EF) as functions of dielectric constants (D), solubility parameters (6), and polarity parameters (P and E -). Solvents studied silicon tetrachloride, carbon disulfide, n pentane. Freon 113, cyclopentane, n-hexane, carbon tetradiloride, diethylether, cyclohexane, isooctane, benzene (reference, EF 100), toluene, trichloroethylene, diethylamine, chloroform, triethylamine, methylene, chloride, tetra-hydrofuran, l,4 dioxane, pyridine, 2 propanol, acetone, ethanol, methanol, dimethyl sulfoxide, and water. Reprinted with permission from Grosjean. ... 

Diethylamine reacts with PtCl2 (vp) to give a 1 1 adduct, which can be transformed into 19b by treatment with methanol, and is thus assigned structure 20. Its low solubility corroborates the zwitterionic nature. 

Secondary amines react (1) with nitrous acid, yielding nilrosamines, yellow oily liquids, volatile in steam, soluble in ether. The secondary amine may be recovered by heating the nitrosamine with concentrated HO, or hydrazines may be formed by reduction of the nilrosamines, eg., methylamline from methylphenylnitrosamine, (i 1 i C. 11 )N 0. reduction yielding unsymmetrical methylphenylhy-drazine, CHjtCni )NHNH , (2) with acetyl or benzoyl chloride, yielding substituted amides, thus, diethylamine plus acetyl chloride to form. V A -diethylacetamide (C lio NOCCH . (3) with benzene sulfonyl chloride, yielding substituted benzene sulfonamides, thus, diethylamine reacts to form N. A -diethylbenzenesulfonamide. Cf,H. lSO>N( C/thJ) . insoluble in NaOH. 

Perfetti et al. (131) described a method for the determination of ethoxyquin in milk. Milk solids were precipitated by adding acetonitrile, and the water-acetonitrile supernatant was washed with hexane to remove fat. The addition of NaCl caused the water-acetonitrile solution to separate into an aqueous phase and an acetonitrile phase, thus separating ethoxyquin from most water-soluble impurities. A large volume of water was then added to the acetonitrile layer, and ethoxyquin was partitioned into hexane and removed at reduced pressure. The residue was dissolved in the mobile phase and analyzed on a 250-mm X 4.6-mm-ID. Ultrasphere ODS column using fluorescence detection with excitation of 230 nm, and emission of 418 nm, respectively. A mixture of water and acetonitrile with a diethylamine-acetic acid buffer was the mobile phase. Recoveries from milk samples fortified at 1, 5, and 10 ng/g averaged 78%, with a coefficient of variation of 5.0%. Low concentrations (less than 1 ng/g) of apparent ethoxyquin were detected in commercial milk samples analyzed by this method. 

Effect of Modifiers Basified with Diethylamine on the Solubility... 

This chapter documents enhancements of the efficiency of SFE extraction of alkaloids from plant matrices using basified modifiers. Hence (1) The pure compound solubility of some free bases in pure supercritical C02 has been measured by investigating the effects of temperature, pressure or density of C02 (2) The solubilities of the alkaloidal salts were compared with those of their free bases in order to evaluate the difference of their solubilities influenced by a changing from free bases to salts (3) Polar solvents such as methanol and water, as initial modifiers, were used for the enhancement of the solubilities (4) The solubilities of the salts by non-basified modifiers such as neat methanol or water were compared with those of methanol or water basified with diethylamine (5) The effect of modifiers employed on the desorption of the compounds from a matrix were measured and compared with each other (5) On the basis of the results of pure compound extractability, SFE was performed on alkaloids from the plant... 

Generally, alkaloidal salts are insoluble in nonpolar solvents but their free bases are quite soluble in the solvents. Therefore, the basified modifier should be introduced into the SFE to solubilize alkaloids in CO,. For the evaluation of the effects of basified modifiers, diethylamine was added to methanol or water at a 10% (v/v) concentration level. Then, the basified modifiers were continuously incorporated into the extraction cell at concentrations of 1, 5, and 10 % (v/v). The effects of methanol basified with diethylamine as a modifier on the solubilities of hyoscyamine (1) and scopolamine (2) are shown in Figure 8. The addition of diethylamine (10% v/v) into methanol dramatically enhanced the solubilities of the alkaloidal hydrochloride salts compared with those of pure methanol alone. This may be due to the fact that methanol basified with diethylamine changed the salts to the free bases. 

When the extractabilities using diethylamine/methanol as a modifier were compared with diethylamine/water, the former was more effective on the extractabilities of hyoscyamine (1) and scopolamine (2) salts than the latter, as seen in the comparison of pure methanol and water. Although the water with added diethylamine was less effective than basifled methanol, it could largely increase the solubilities wben compared with pure water, similar to the comparison of basic methanol with pure methanol (Figure 9). 

Figure 8. Comparison of the solubilities of hyoscyamine (A) and scopolamine (B) hydrochloride using methanol basified with diethylamine (10% v/v) with those of pure methanol at 60 C, 34.0 MP [39]. Reprinted from J. Chromalogr. A, 863, Y. H. Choi et al., Strategies for supercritical fluid extraction of hyoscyamine and scopolamine salts using basified modifiers, 47-55,1999, with permission from Elsevier Science.

Figure 10. Effect of methanol (A) and water (B) basified with diethylamine (10% v/v) as a modifier on the solubilities of ephedrine derivative hydrochloride salts in C02 at 80 °C and 34.0 MPa. ME = methylephedrine (3) NE = norephedrine (4) E = ephedrine (5) PE = pseudoephedrine (6) [41]. Reproduced with permission from Vieweg Publishing 1999.

In both results of solubility and desorption from filter papers, diethylamine in methanol as a modifier was found to offer greater efficiency for SFE of the alkaloids than any other modifiers employed. The yields of hyoscyamine (1) and scopolamine (2) from the roots and aerial parts by SFE and conventional organic solvent extraction are listed in Tables 2 and 3. The SFE yields from both plant parts were greatly enhanced by the addition of methanol basified with diethylamine. From the results of solubility and desorption from filter paper, methanol and diethylamine/methanol (10% v/v) were much more efficient for both compounds than water and diethylamine/water (10% v/v) because of their low miscibility with C02. The extraction profile of hyoscyamine (1) when present in plant material was in good agreement with that when extracted as a pure compound. However, in the case of scopolamine (2), there... 

The acceptor stream in this instance is limited to distilled water. The actual color development occurs after the alkaline buffer is premixed with the ammonium purpurate indicator and the resultant stream is admitted to the test solution. Since the pH at which color development is recorded is quite critical, the alkaline buffer used is the water soluble organic base, diethylamine, which has been adjusted to a pH of 11.7. 

Tilorone hydrochloride, 2,7—bis [2-(diethylamine) ethoxy]-9H-fluorene-9-one dihydrochloride, is an orange solid which is highly water soluble at neutral and acidic pH. The compound is anhydrous and melts between 234-234.5 °C with decomposition. The molecular weight is 483.47. Tilorone-HC1 has an intense absorption band at 270 nm in water. The pKa of the amine functions are 8.64 and 9.27, respectively the compound is stable in acid or base. The synthesis of tilorone hydrochloride was outlined by Andrews et al.10), and Gaur and Wacker15). 

BioHi2 2CH3CN, and with BioHi2-2(CH3)2S, and by the reaction of the last compound with diethylamine/ i-butyl-amine, ammonium hydroxide, and ammonia. The preparation described below is for the triethylammonium salt. Most of the reactions reported for the BioHio anion start with the ammonium salt. The triethylammonium salt will work equally well in most cases. However, the solubility characteristics of the two salts are different. Reference 3 reports synthesis details for the ammonium salt, should it be required. 

The water-soluble complex cij-PtCl2(TPPTS)2 has been used as a catalyst for the 1,4-addition of diethylamine to isoprene (Eq. 36). Water-... 

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