Glycols 1,4-dioxanes

Aminabhavi, T.M., Gopalakrishna, B., 1995. Density, viscosity, refractive index, and speed of sound in aqueous mixtures of A,A-dimethylformamide, dimethylsulfoxide, A,A-dimethylace-tamide, acetonitrile, ethylene glycol, diethylene glycol, 1,4-dioxane, tetrahydrofuran, 2-methoxyethanol, and 2-ethoxy-ethanol at 298.15 K. J. Chem. Eng. Data 40, 856-861. Barzegar-Jalali, M., Jouyban-Gharamaleki, A., 1996. Models for calculating solubility in binary solvent systems. Int. J. Pharm. 140, 237-246. 

HC0N(CH3)2, also possess exceptional solvent properties. The alkyl-glycols, dioxan and dimethyl-formamide should be used with caution, however, as their hot vapours are poisonous. 

Absorption spectra, emission spectra and excitation polarization spectra were recorded in a propylene glycol-dioxane glass at 200 K. Comparison was made with the reference chromophore 2-ethylnaphthoate (NAEt). 

Figure 5. Plots of AGt°(OH ) for water + co-solvent at 25°C against composition of the mixture with the following co-solvents (O) methanol ( ) ethylene glycol (%) dioxan (A) dimethyl sulfoxide ...

An unidentiffed compound, not polonium hydroxide and presumed to be P0OCI2, was obtained by the evaporation of a dilute hydrochloride acid containing polonium. The residue is soluble in polar organic solvents such as ethanol, ethylene glycol, dioxane, acetone, and methyl ethyl ketone. It is insolnble in benzene or chloroform. 

HjSO 295, 505 nm (E 26ft 315). Freely sol in the lower alcohols, in ethylene glycol, dioxane, glacial acetic acid. Slightly sol in water, acetone, chloroform, ethyl acetate. Practically insol in ether, petr ether. LD, in mice (mg/kg) 0.471 s.c.j 0.440 orally (Dybing). 

Soluble in water below 38°C, ethanol, propylene glycol, dioxane, methanol, isopropyl alcohol, dimethyl sulfoxide, dimethyl formamide, etc. 

Dichloroethane Ethylene glycol Dioxane Diglyme Triglyme... 

Solubility considerations frequently dictate the use of solvents other than pure water for organic voltammetry aqueous mixtures containing varying amounts of such miscible solvents as glycols, dioxane, acetonitrile, alcohols, Cellosolve, or acetic acid have been used. Anhydrous media such as acetic acid, formamide, di-ethylamine, and ethylene glycol have also been investigated. Supporting electrolytes are often lithium or tetraalkyl ammonium salts. 

Polymers of acrylic and methacrylic acids and their salts are hard, brittle, transparent materials. Poly(acrylic acid) and poly(methacrylic acid) are soluble in such polar solvents as methanol, ethanol, ethylene glycol, dioxan, dimethyl-formamide and water but are insoluble in non-polar solvents such as aliphatic and aromatic hydrocarbons. Monovalent metal and ammonium salts of these polymers are generally soluble in water. 

Homologous mono-alkyl ethers of ethylene glycol, such as monoethyl glycol (or 2-ethoxyethanol), HOC2H4OC2H5, form excellent solvents as they combine to a large extent the solvent properties of alcohols and ethers. The monoethyl and the monomethyl members have the technical names of ethyl cellosolve and methyl cellosolve respectively. Dioxan... 

Hydrogenations with coppcr-chromium oxide catalyst are usually carried out in the liquid phase in stainless steel autoclaves at pressures up to 5000-6000 lb. per square inch. A solvent is not usually necessary for hydrogenation of an ester at 250° since the original ester and the alcohol or glycol produced serve as the reaction medium. However, when dealing with small quantities and also at temperatures below 200° a solvent is desirable this may be methyl alcohol, ethyi alcohol, dioxan or methylcyc/ohexane. 

Another method for the hydroxylation of the etliylenic linkage consists in treatment of the alkene with osmium tetroxide in an inert solvent (ether or dioxan) at room temperature for several days an osmic ester is formed which either precipitates from the reaction mixture or may be isolated by evaporation of the solvent. Hydrolysis of the osmic ester in a reducing medium (in the presence of alkaline formaldehyde or of aqueous-alcoholic sodium sulphite) gives the 1 2-glycol and osmium. The glycol has the cis structure it is probably derived from the cyclic osmic ester ... 

Solvent, wt % Methanol, Ag/AgCl Ethanol, Ag/AgCl 2-Propanol, Ag/AgCl Acetone, Ag/AgCl Dioxane, Ag/AgCl Ethylene glycol, Ag/AgCl Methanol, calomel Dioxane, calomel... 

Diethylene glycol readily dehydrates using an acid catalyst to make 1,4-dioxane [123-91 -1] (eq. 5). 

Organophosphorus Derivatives. Neopentyl glycol treated with pyridine and phosphorus trichloride in anhydrous dioxane yields the cycHc hydrogen phosphite, 5,5-dimethyl-l,3-dioxaphosphorinane 2-oxide (2) (32,33). Compounds of this type maybe useful as flameproofing plasticizers, stabilizers, synthetic lubricants, oil additives, pesticides, or intermediates for the preparation of other organophosphoms compounds (see Flame retardants Phosphorus compounds). 

Acetals andKetals. Acetals of 1,3-diols are prepared by refluxing the diol with the aldehyde in the presence of an acid catalyst, even in an aqueous medium. The corresponding ketals are more difficult to prepare in aqueous solution, but cycHc ketals of neopentyl glycol, eg, 2-butyl-2-ethyl-5,5-dimethyl-l,3-dioxane (3), can be prepared if the water of reaction is removed azeotropicaHy (34). 

Cychc carbonates are prepared in satisfactory quaUty for anionic polymerization by catalyzed transesterification of neopentyl glycol with diaryl carbonates, followed by tempering and depolymerization. Neopentyl carbonate (5,5-dimethyl-1,3-dioxan-2-one) (6) prepared in this manner has high purity (99.5%) and can be anionically polymerized to polycarbonates with mol wt of 35,000 (39). 

The addition product, C QHgNa, called naphthalenesodium or sodium naphthalene complex, may be regarded as a resonance hybrid. The ether is more than just a solvent that promotes the reaction. StabiUty of the complex depends on the presence of the ether, and sodium can be Hberated by evaporating the ether or by dilution using an indifferent solvent, such as ethyl ether. A number of ether-type solvents are effective in complex preparation, such as methyl ethyl ether, ethylene glycol dimethyl ether, dioxane, and THF. Trimethyl amine also promotes complex formation. This reaction proceeds with all alkah metals. Other aromatic compounds, eg, diphenyl, anthracene, and phenanthrene, also form sodium complexes (16,20). 

Perchloric acid (79% HCIO4/CH2CI2, 0°, 1 h 25°, 3 h, 87% yield) and periodic acid (aq. dioxane, 3 h, quant, yield) cleave 1,3-dioxolanes the latter drives the reaction to completion by oxidation of the ethylene glycol that forms. Yields are substantially higher from cleavage with perchloric acid (3 AHCIO4/THF, 25°, 3 h, 80% yield) than with hydrochloric acid (HCl/HOAc, 65% yield)... 

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