Dioxane methanols

Physical properties of the acid and its anhydride are summarized in Table 1. Other references for more data on specific physical properties of succinic acid are as follows solubiUty in water at 278.15—338.15 K (12) water-enhanced solubiUty in organic solvents (13) dissociation constants in water—acetone (10 vol %) at 30—60°C (14), water—methanol mixtures (10—50 vol %) at 25°C (15,16), water—dioxane mixtures (10—50 vol %) at 25°C (15), and water—dioxane—methanol mixtures at 25°C (17) nucleation and crystal growth (18—20) calculation of the enthalpy of formation using semiempitical methods (21) enthalpy of solution (22,23) and enthalpy of dilution (23). For succinic anhydride, the enthalpies of combustion and sublimation have been reported (24). 

AcOOH, KBr, AcOH, NaOAc, 1.5 h, 20°, 82-92% yield. The SMOM group is stable to Bu4N F NaOMe/MeOH 4 N NaOH/dioxane/methanol A -iodosuccinimide, cat. trifluoromethanesulfonic acid. 

Normal /, /i -Oxydipropionitrile Carbowax (400, 600, 750, etc.) Glycols (ethylene, diethylene) Cyanoethylsilicone Saturated hydrocarbons, e.g. hexane, heptane aromatic solvents, e.g. benzene, xylene saturated hydrocarbons mixed with up to 10 per cent dioxan, methanol, ethanol, chloroform, methylene chloride (dichloromethane)... 

With potassium /m-butoxide in tetrahydrofuran, the dibromodihydro-3//-l-benzazepines 7 (R1 = H, F, Cl) undergo syn dehydrobromination to synthetically useful alkenyl bromides, e.g. 8 (R1 = Cl), accompanied by small amounts of debrominated materials, e.g, 9 (R1 = Cl), and the 3-fcrf-butyl ethers, e.g. 10b(R1 = Cl, R2 = -Bu).78 In contrast, with sodium hydroxide, or with sodium methoxide in dioxane/methanol, the yields of bromo compounds 8 decrease, and significant amounts of the methyl ethers, e.g. 10a (R1 = Cl R2 = Me), arc produced. A mechanistic rationale for these reactions has been offered. 

The arylation of potassium phenoxide has been studied by Litvak and Shein (1976). In the absence of crown ether the rate of reaction with p-nitrobromobenzene in various solvents increases in the order dioxan < methanol < pyridine < DMSO. In the presence of either 18-crown-6 [3] or dibenzo-18-crown-6 [11], the order of the reaction rates in dioxan and methanol is reversed (Table 22). The effect of crown ether addition on the rate... 

Cellulose triacetate Acetone, chloroform, 1,4-dioxane Methanol, diethyl ether... 

More recently, Otocka measured the Rf values for several polystyrenes using dioxane-methanol and dioxane-2-propanol 0 solvents (16). The results shown in Table I indicate that despite a great variety in the... 

Dioxane-methanol (50 50), AQ28, AQ55 -water (82 18), AF60, AF6i... 

Molar mass distributions of PDADMAC were also determined by fractionation using dioxane/methanol system [144] and from sedimentation velocity measurements in 1 m NaCl solution [134]. The molar mass calculations were based on the s-M relation [134] ... 

Figure 1.17 shows the comparison of theory and experiment for preferential adsorption coefficient X of poly(alkyl methacrylate)s in 1,4-dioxane-methanol. 

A quantitative agreement was found between theory and the experimental results dealing with the dependence of the preferential adsorption coefficient X with the composition, in the cases that were chosen as examples Poly(alkyl methacrylates )/l, 4 - dioxane/methanol [120],... 

It was also reported experimental results about the preferential adsorption of a family of poly(dialkyl itaconates) [poly[l - (alkoxycarbonyl) - 1 - [(alkoxycar-bonyl) - methyl] ethylene] in 1,4 - dioxane/methanol. The chemical structures of the polymers are shown Fig. 1.18 [122],... 

Fig. 1.17 Comparison of theory and experiment for preferential adsorption coefficient, X, of poly(alkyl methacrylate)s in 1,4-dioxane-methanol. (pso = methanol volume fraction). Points Experimental results from ref. [6], (o) PMMA (alkyl = Me) (A) PEMA (Et) ( ) PiBM (iBu). Association equilibria theory. (2-A) Calculated with the parameter values shown in Table I and numbered as 4-6, Curves (a) PMMA (b) PEMA, (c) PiBMA. (2-B) Calculated with the parameter values shown in Table I and numbered as 10-12. Curves (a) PMMA (b) PEMMA (c) PiBMa. (From ref. [120])...

Silica Toluene-dioxane-methanol-conc. ammonium hydroxide (2 5 2 1)... 

C-3 Solvent extraction of Cholesterol from Ga11 stones 207 diethyl ether acetone dioxane methanol... 

Dioxane/methanol (1 2, v/v) CH2CI2/methanol (5 1, v/v) Methyl cellosolve... 

A weighed amount of lignin is dissolved or suspended in dioxane-methanol (9 1, v/v) and one drop of water/2ml solvent (approximately 5 mg of lignin ml-1 of solvent). Diazomethane is added to the solution under a stream of nitrogen over a 5-min period at room temperature. (The reaction should be conducted in a well-ventilated hood.) The diazomethane is conveniently prepared from N-methyl-N-nitroso-p-toluenesulfonamide (Merck-Schuchardt, Aldrich, Fisher, Fluka, and others) in a special reaction flask as described by Schlenk and Gellerman (1960). After a reaction time of approximately 20min, the procedure is repeated and diazomethane is again added over a 5-min period. The pro-... 

A reaction vessel was charged with 100 ml 1,4-dioxane/methanol, 3 2, aniline (0.93 g), the product from Step (2.0 g), 2.5 ml concentrated HCl and 5 ml of water and cooled to 0° to — 3°C. While at this temperature, 5 ml of an aqueous solution of sodium nitrite (0.72 mg) was added over 20 minutes followed by 10 ml solution of NaOH (1.38 g) and the mixture stirred 2 hours. Thereafter, the product was purified as in Step 1 and 1.6 g product isolated. 

The photolysis of azide 35 for 80 minutes in dioxane methanol solution at room temperature affords a 92 % yield of the distillable lH-l,3-diazepine 36. Using diisopropylamine as the trapping agent a 76 % yield of the corresponding diisopropylamino derivative is obtained. 

The neighboring-group concept of Winstein has been used to explain the difference in reactivity exhibited by anomeric pairs of halides. This suggestion is by no means improbable, and would explain the facts that tri-0-benzoyl-/3-D-ribopyranosyl bromide is 19 times more reactive at 20° in 1 9 dioxane-methanol than is the a anomer, and that the rate for the trans-l3 chloride shows an 85-fold increase over that of the cis-a chloride. However, in view of the properties of the series XXVII to XXX, steric effects from the whole molecule may be equally important, although the disadvantage of this concept is that hindrance as assessed from models is difficult to define precisely. It is of interest to compare the rates of methanolysis of tri-O-benzoyl-a-D-xylopyranosyl bromide and of tri-O-acetyl-a-D-xylopyranosyl bromide [10 fc ° = 51(sec ) in 1 9 dioxane-methanol and = 139(sec 0 in 100% methanol, respectively]. Although the... 

In general the synthesis of suitably protected amino acid and peptide hydrazides from the corresponding alkyl or aryl esters by reaction with hydrazine hydrate is carried out in alcohols or DMF at ambient temperature.P However, with C-terminal branched amino acids such as valine or isoleucine, or larger peptides, more vigorous conditions are required, i.e. higher temperature (25-80°C) and longer reaction times. To avoid formation of symmetrical bis(A-acyl-aminoacyl)hydrazides an excess of hydrazine hydrate or hydrazine is recommended, which also enhances the reaction rates. In this context, the solvent is known to play an important role, with alcohols being more appropriate than DMFP 0 or solvent mixtures such as dioxane/methanol.f l The use of hydrazine hydrate without any solvent has also been reported. ... 

For some silanediols XMeSi(OH)2 kinetic data and mechanistic considerations already exist for the condensation in organic solvents (dioxane, methanol) [2-4], which are interesting for comparision with results for the reaction in water. 

Nitroanthranylazo (formula 5.1) has been proposed for the determination of Li [47]. The colour reaction is carried out in aqueous acetone made alkaline with KOH. The absorbance is measured at 530 nm (e= 1.2-10 ). The colour intensity depends on the medium used (water-acetone, dioxan, methanol, DMF), excess of Nitroanthranylazo, and ionic strength. In the determination of 2 pg of lithium, there is no interference of 200 pg Rb, 100 pg Mg or Ca, 50 pg Ba, Sr, or Na, The method has been applied for determination of lithium in ferrites [48]. 

Styrene, divinyl-benzene (DVB), dioxane, methanol and cyclohexane were purified according to published methods [ 12] Styrene-divinylbenzene copolymer (X AD-8) was procured from Fluka... 

Figure 5. Absorption spectra of and 8, solvent 5% dioxane/methanol. (Reproduced with permission from Ref. 16.)...

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