Aqueous ethanol solution

B) Phenacyl and p-Bromophenacyl esters. The sodium salt of an acid in aqueous-ethanolic solution will react with phenacyl bromide, CjHjCOCHgBr, and with p-bromophenacyl bromide, BrC,H4COCH2Br... 

C) Phenacyl and p-Bromophenacyl esters. Ammonium salts in aqueous-ethanolic solution do not however usually condense satisfactorily with phenacyl and />-bromophenacyl bromide. The aqueous solution of the ammonium salt should therefore be boiled with a slight excess of sodium hydroxide to remove ammonia, and the solution then cooled, treated with hydrochloric acid until just alkaline to phenol-phthalein, and then evaporated to dryness. The sodium salt is then treated as described (p. 349) to give the ester. Filter the ester, and wash with water to remove senium halide before recrystallisation. 

We chose benzyli dene acetone (4.39, Scheme 4.11) as a model dienophile for our studies. The uncatalysed Diels-Alder reaction of this compound with cyclopentadiene is slow, justifying a catalytic approach. Reaction of 4.39 with paraformaldehyde and dimethyl amine under acidic conditions in an aqueous ethanol solution, following a literature procedure, produced the HCl salt of 4.42 (Scheme 4.11). The dienophile was liberated in situ by adding one equivalent of base. 

As actually carried out the mixed aldol condensation product 1 3 diphenyl 2 propen 1 one has been isolated in 85% yield on treating benzaldehyde with ace tophenone in an aqueous ethanol solution of sodium hydroxide at 15-30°C... 

Difluoroethanol [359-13-7], F2CHCH2OH, is a colorless Hquid with an alcohol-like odor mp, 28.2°C, bp, 96°C d[, 1.3084 n], 1.3320 heat of combustion, —1026 kJ/mol(—245.3 kcal/mol). It is stable to distillation and miscible with water and many organic solvents. As expected, its acidity Hes between that of 2-fluoroethanol and 2,2,2-trifluoroethanol both ia the gas phase (25) and ia 50% aqueous ethanol solution (26), where its of 1.0 x 10 is about 4.8 times smaller than that of trifluoroethanol. 

Figure 5.8 shows a typieal plot of log (/ind) versus (log S") for Cyanazine erystallized form aqueous ethanol solution. 

Hurley, M.A., Jones, A.G. and Drummond, J.N., 1995. Crystallization kinetics of cyanazine precipitated from aqueous ethanol solutions. Chemical Engineering Research and Design, 73B, 52-57. 

An aqueous ethanol solution of acrylamide, 2,2 -methylenebisacrylamide as cross-linked agent and third acrylamide derivative, is dispersed in an n-alkane. Then three monomers are polymerized to spherical porous gels. The effect of the composition of the third monomer on the exclusion limits of the gel in size-exclusion chromatography has been investigated (82). 

Similarity with cobalt is also apparent in the affinity of Rh and iH for ammonia and amines. The kinetic inertness of the ammines of Rh has led to the use of several of them in studies of the trans effect (p. 1163) in octahedral complexes, while the ammines of Ir are so stable as to withstand boiling in aqueous alkali. Stable complexes such as [M(C204)3], [M(acac)3] and [M(CN)5] are formed by all three metals. Force constants obtained from the infrared spectra of the hexacyano complexes indicate that the M--C bond strength increases in the order Co < Rh < [r. Like cobalt, rhodium too forms bridged superoxides such as the blue, paramagnetic, fCl(py)4Rh-02-Rh(py)4Cll produced by aerial oxidation of aqueous ethanolic solutions of RhCL and pyridine.In fact it seems likely that many of the species produced by oxidation of aqueous solutions of Rh and presumed to contain the metal in higher oxidation states, are actually superoxides of Rh . ... 

These compounds usually give many of the reactions characteristic of phenols and were long considered to exist completely in the hydroxy form (see, for example, reference 42). It has been noted that the ultraviolet spectra of aqueous ethanolic solutions of hydroxy-acridines varied with changes in the composition of the solvent, and this phenomenon has been interpreted in terms of the equilibria 132 133 and 134 135. Some compounds of these types show... 

In the search for new fluorometric reagents for trace metal determinations, ferroin-type compounds, namely 2-(2-pyridyl)-2//- and 2-(3-isoquinolyl)-3//-imidazo[4,5-/i]quinolines, and their silver, lead, and zinc chelates were tested for luminiscence in aqueous ethanol solutions at various pH values (80TAL1021). 

Treatment of 2-amino-3-hydroxypyridine (185) with 2-chloro-3-nitropyridine (193) easily provided intermediate 194. Attempts to cyclize 194 with potassium hydroxide in aqueous ethanolic solutions failed, probably due to strong H-bonding. Similarly as with phenoxazines, the cyclization smoothly proceeded in DMSO to give low yield (31%) of 1,9-diazaphenoxazine (195) (Scheme 30) (74CC878, 76JHC107, 77H391). 

Sodium hydrogen telluride, (NaTeH), prepared in situ from the reaction of tellurium powder with an aqueous ethanol solution of sodium borohydride, is an effective reducing reagent for many functionalities, such as azide, sulfoxide, disulfide, activated C=C bonds, nitroxide, and so forth. Water is a convenient solvent for these transformations.28 A variety of functional groups including aldehydes, ketones, olefins, nitroxides, and azides are also reduced by sodium hypophosphite buffer solution.29... 

Benzoin Condensation. The benzoin condensation is a related reaction consisting of treating an aromatic aldehyde with potassium cyanide or sodium cyanide usually in an aqueous ethanolic solution. Breslow studied the effects of inorganic salts on the rate... 

The electrochemical behavior of an aqueous/ethanol solution of [Ir(sat)2]Cl, satH = salicylaldehyde thiosemicarbazone (235), has been studied on mercury. A two-electron, ligand-based reduction at —1.09 V vs. SCE (independent of pH) is observed at fast scan rates.406... 

Tanaka S, Oda Y, Ataka M, et al. Denaturation and aggregation of hen egg lysozyme in aqueous ethanol solution studies by dynamic light scattering. Biopolymers 2001 59 370-379. 

The inclusion complexes of 3-R 4-R2-disubstituted l,2,5-oxadiazole-2-oxide with polycyclic derivatives of gluco-pyranose were prepared by heating an aqueous ethanolic solution of /3-cyclodedextrin with the corresponding furazan... 

Derechin and coworkers noted the anomalous behavior of gramicidin A in absolute ethanol79. The apparent partial specific volume increased with decreasing concentration of gramicidin. The same was not true for aqueous-ethanol solutions. 

Boiling aqueous ethanolic solutions of 2-benzothiazolylaminomethy-lenemalonates (1351) in the presence of sodium hydroxide for 30 min gave 1-substituted 2,4-dioxopyrimidine-5-carboxylic acids (1352) in 52-70% yields (79GEP2810863, 79SAP1053). 

A/-(Furo[3,2-i>]pyridin-2-yl)aminomethylenemalonates (1432) were stirred in a 1.2 N ethanolic solution of potassium hydroxide at ambient temperature for 1.5 hr, or in a 2 N ethanolic solution of sodium hydroxide under reflux for 6 hr, to give the 3-carboxylic acid (1433) in 33-61% yield (84G211). Solutions of N-(furopyridin-2-yI)aminomethylenemalonates (1432) in 2 N hydrochloric acid were refluxed for 2 hr to afford 2-aminofuro-pyridine-3-carboxylates (1434) in 55% and 82 % yields. When the 3-ethoxy-carbonyl derivative (1432, R = Et) was heated in a boiling aqueous ethanolic solution of potassium hydroxide for 2 hr, 2-pyridinylacetic acid (1435) was obtained in 47% yield. The treatment of the 4-nitrophenyl ester of 1432 (R = 4-N02Ph) with ethyl iodide in DMF in the presence of potassium carbonate gave the ethyl ester of 1432 (R = Et) in 91% yield (84G211). 

The chemical oxidation of 1,3,5-triarylformazans to tetrazolium salts was first accomplished in 1894 [127], Almost no attention was given to these compounds for about 50 years after their discovery. This situation began to alter markedly because of the application of tetrazolium salts in histochemical, pharmacological, and other biomedical research areas [128]. Specifically, the tetrazolium salt is reduced to a colored formazan derivative by reducing enzymes found only in metabolically active cells. Anodic transformation of for-mazans to tetrazolium salts was performed in acetonitrile solution using cotrolled potential electrolysis [17,129], In our view this reaction could be considered as a method of choice for the preparation of tetrazolium salts. The products were obtained in high yield and the electrolysis can be performed in a divided cell under constant current and decoloration of the solution indicates the end point of the reaction. Recently the anodic oxidation of formazans to tetrazolium salts was performed successfully in aqueous ethanol solution [130]. 

These composites were prepared by mixing a fluorocarbon solution of the perfluorinated PPl dendrimers with an aqueous ethanolic solution of Pd, thereby forming an emulsion. After phase separation, the fluorous phase, which contains the dendrimer-encapsulated Pd +, was treated with a reducing agent yielding zero-valent Pd nanoclusters trapped within the dendrimer (Fig. 24). 

Photolytic. When propachlor in an aqueous ethanolic solution was irradiated with UV light (>, = 290 nm) for 5 h, 80% decomposed to the following cyclic photoproducts W-isopropyloxindole, W-isopropyl-3 hydroxyoxindole, and a spiro compound. Irradiation of propachlor in an aqueous solution containing riboflavin as a sensitizer resulted in completed degradation of the parent compound. 3-Hydroxypropachlor was the only compound identified in trace amounts which formed via ring hydroxylation (Rejtb et al, 1984). Hydrolyzes under alkaline conditions forming W-isopropylaniline (Sittig, 1985) which is also a product of microbial metabolism (Novick et al., 1986). 

Batch crystallization studies of D-fructose from aqueous ethanolic solutions demonstrate that crystal growth rate is dependent on supersaturation (possibly to the 1.25 power), ethanol content and temperature. It appears that solution viscosity also has an effect. Growth rates of up to 1 pm/mln were measured. 

The seed crystals of D-fructose were obtained by ball milling crystals produced by spontaneous nucleatlon from an aqueous ethanolIc solution of fructose and allowing them to stand at room temperature in slightly supersaturated ethanolIc solution until the desired crystal size (20-40 microns) was achieved. They were then stored at 30 C in saturated, anhydrous ethanol to prevent further crystal growth. A portion of this slurry was added to the crystallizer as the seeds. 

Properties of EthanolIc Fructose Solutions. Published information on the properties of aqueous ethanolic fructose solution is very limited. As a result, solubility data from 25 to 60 °C was measured (Figure 1) and will be published separately. The equilibrium fructose/water mass ratio for zero alcohol, ranges from over 4 at 25 C to over 8 at 60 C (7,8). It can be seen that reasonable yields will only result with high alcohol additions (E/W at least 2). This is the range used in this study. Aqueous ethanolic solutions have a wide range of viscosities. These were measured at operating conditions using a Rheomat concentric cylinder viscometer. 

Figure 8. Size spread coefficient, q vs E/W for fructose crystallization from aqueous ethanol solutions.

The kinetic behaviour of fructose crystallization from aqueous ethanolIc solutions, typical in composition to those operated on an industrial scale, is strongly dependent on supersaturation, solvent composition and temperature. Provided the supersaturation is kept below 35 C of subcooling, nucleation does not occur. 

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