Physical Properties of Methanol

Critical Pressure, Kg/cm (PSIA) 81.12(1153.95) Solubility in Water, 20-C (68T) Completely Miscible 

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Reagent-grade methanol and salts manufactured by Nakarai Chemicals, Ltd. (Tokyo) were used without further purifications distilled water was used. The physical properties of methanol and water were compared with the published data (3). Carbon dioxide was supplied from a commercial cylinder and the purity was confirmed by gas chromatogram to be greater than 99.8%. 

Physical properties of methanol Molecular weight is 32, normal boiling point is 65 C, and the density of vapor is... 

Methanol, or as it is termed in full methyl alcohol, with the chemical formula CH3OH is the first of the long series of alcohols. Its molecular weight is 32.04 and it is a neutral, colourless liquid in pure condition having an odour similar to that of ethyl alcohol. Methanol dissolves well with other alcohols, esters, ketones as well as with aromatic hydrocarbons and water. It can be less well mixed with fats and oils. It dissolves a number of organic substances including numerous salts. The most important physical data for methanol are assembled in Tables 3.1 to 3.5. Further data on the physical properties of methanol can be taken from the literature under [3.3-to 3.10]. 

Figure 8-3 The hydrophobic and hydrophilic parts of methanol and 1-pentanol (space-filling modeis). The poiar functionai group dominates the physical properties of methanol The molecule is completely soluble in water but only partially so in hexane. Conversely, the increased size of the hydrophobic part in 1-pentanol leads to infinite solubility in hexane but reduced solubility in water (Table 8-1).

Methanol applications can be divided into three major end-user categories chemical feedstock, fuel and fuel additives, and miscellaneous applications. The first two users cover more than 95% of methanol consumption and are discussed in the previous chapters of this book [1, 2], This chapter focuses on various methanol applications that are not covered in previous discussions. Most of these applications utilize the physical properties of methanol, except for the production of single-cell protein and sewage treatment, which use methanol as a substrate to supply the energy needed in the growth of microorganisms. A brief discussion of each of these applications of methanol is given. 

The physical properties of methanol, its melting point, boiling point and solubility in water, approach the ideal for soluble fuels it is also resistant to reduction at the cathode. However, it is inflammable and, although it can be electrochemically oxidized to carbon dioxide and water, its exchange current density is small and suitable inexpensive catalysts to yield high current densities are not yet known. This latter drawback is the one holding back the commercial development of the methanol fuel cells. 

The slightly different physical properties of deuterium allow its concentration in ordinary hydrogen (or the concentration of a deuterium-containing compound in a hydrogen compound) to be determined. Exchange of deuterium and hydrogen occurs and can be used to elucidate the mechanism of reactions (i.e. the deuterium is a non-radioactive tracer). Methanol exchanges with deuterium oxide thus ... 

Physical properties of A-4-thiazoline-2-one and derivatives have received less attention than those of A-4-thiazoline-2-thiones. For the protomeric equilibrium, data obtained by infrared spectroscopy favors fbrm 51a in chloroform (55, 96, 887) and in the solid state (36. 97. 98) (Scheme 23). The same structural preference is suggested by the ultraviolet spectroscopy studies of Sheinker (98), despite the fact that previous studie.s in methanol (36) suggested the presence of both 51a and... 

Selected physical properties of various methacrylate esters, amides, and derivatives are given in Tables 1—4. Tables 3 and 4 describe more commercially available methacrylic acid derivatives. A2eotrope data for MMA are shown in Table 5 (8). The solubiUty of MMA in water at 25°C is 1.5%. Water solubiUty of longer alkyl methacrylates ranges from slight to insoluble. Some functionalized esters such as 2-dimethylaniinoethyl methacrylate are miscible and/or hydrolyze. The solubiUty of 2-hydroxypropyl methacrylate in water at 25°C is 13%. Vapor—Hquid equiUbrium (VLE) data have been pubHshed on methanol, methyl methacrylate, and methacrylic acid pairs (9), as have solubiUty data for this ternary system (10). VLE data are also available for methyl methacrylate, methacrylic acid, methyl a-hydroxyisobutyrate, methanol, and water, which are the critical components obtained in the commercially important acetone cyanohydrin route to methyl methacrylate (11). 

Nitrotoluene [99-99-0] crystallizes in colorless rhombic crystals. It is only slightly soluble in water, 0.044 g/100 g of water at 30°C moderately soluble in methanol and ethanol and readily soluble in acetone, diethyl ether, and benzene. The physical properties of -nitrotoluene are Hsted in Table 11. 

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). 

Methanol synthesis will be used many times as an example to explain some concepts, largely because the stoichiometry of methanol synthesis is simple. The physical properties of all compounds are well known, details of many competing technologies have been published and methanol is an important industrial chemical. In addition to its relative simplicity, methanol synthesis offers an opportunity to show how to handle reversible reactions, the change in mole numbers, removal of reaction heat, and other engineering problems. 

The physical properties of the anhydrate form and two polymorphic monohydrates of niclosamide have been reported [61], The anhydrate form exhibited the highest solubility in water and the fastest intrinsic dissolution rate, while the two monohydrates exhibited significantly lower aqueous solubilities. In a subsequent study, the 1 1 solvates of niclosamide with methanol, diethyl ether, dimethyl sulfoxide, N,/V -dimethyl formamide, and tetrahydrofuran, and the 2 1 solvate with tetraethylene glycol, were studied [62], The relative stability of the different solvatomorphs was established using desolvation activation energies, solution calorimetry, and aqueous solubilities. It was found that although the nonaqueous solvates exhibited higher solubilities and dissolution rates, they were unstable in aqueous media and rapidly transformed to one of the monohydrates. 

Fe(Cp-C0NHCH2S03)2] anion have been identified (TTF)2[Fe(Cp-CONHCH2 S03)2] and the solvated (TTF)2[Fe(Cp-C0NHCH2S03)2]-2CH30H. Both crystal structures contain face-to-face dimers, with the main structural differences probably attributed to hydrogen bonding to the cocrystallized methanol. No physical properties of these salts have yet been published. 

As has been suggested in the previous section, explanations of solvent effects on the basis of the macroscopic physical properties of the solvent are not very successful. The alternative approach is to make use of the microscopic or chemical properties of the solvent and to consider the detailed interaction of solvent molecules with their own kind and with solute molecules. If a configuration in which one or more solvent molecules interacts with a solute molecule has a particularly low free energy, it is feasible to describe at least that part of the solute-solvent interaction as the formation of a molecular complex and to speak of an equilibrium between solvated and non-solvated molecules. Such a stabilization of a particular solute by solvation will shift any equilibrium involving that solute. For example, in the case of formation of carbonium ions from triphenylcarbinol, the equilibrium is shifted in favor of the carbonium ion by an acidic solvent that reacts with hydroxide ion and with water. The carbonium ion concentration in sulfuric acid is greater than it is in methanol-... 

The Acid Effect. The possible mechanistic role of hydrogen atoms in the current radiation grafting work becomes even more significant when acid is used as an additive to enhance the copolymerisation. At the concentrations utilised, acid should not affect essentially the physical properties of the system such as precipitation of the polystyrene grafted chains or the swelling of the polyethylene. Instead the acid effect may be attributed to the radiation chemical properties of the system. Thus Baxendale and Mellows (15) showed that the addition of acid to methanol increased G(H2) considerably. The precursors of this additional hydrogen were considered to be H atoms from thermalised electron capture reactions, typified in Equation 5. 

Owing to the unsatisfactory physical properties of the triglycerides, the oils are converted into fatty acid esters of low alcohols such as methanol or ethanol. 

Ross, K. D. 1978A. Effects of methanol on physical properties of a- and /3-lactose. J. Dairy Sci. 61, 152-158. 

This procedure, with slight modifications depending on the physical properties of the sulfide and sulfoxide in question, has been used to prepare a variety of sulfoxides as illustrated by examples provided in Table I In the case of very insoluble sulfides, co solvents such as methanol or dioxane may be employed Very... 

Depending on the amount of amine used and on the milling time, the reaction mass either had a pastelike consistency or that of a fluid dispersion. The experiments were intended to establish some parameters (duration of mechanical processing, amount of diamine and complexing agent, etc.) and correlate them to characterize the polymers obtained, and to determine certain chemical and physical properties of the polymer. In all cases, the samples were purified by extraction in a Soxhlet apparatus with water or alcohol to remove unreacted ethylenediamine and metallic salts. The extractions were carried out until constant weight was obtained. Total removal of chloride was determined by silver nitrate. Purified samples were then washed with methanol, dried, and analyzed. 

The volumetric gas-liquid mass transfer coefficient, khaL, largely depends on power per unit volume, gas velocity (for a gassed system), and the physical properties of the fluids. For high-viscosity fluids, kLaL is a strong function of liquid viscosity, and for low-viscosity fluids (fi < 50 mPa s), kLaL depends on the coalescence nature of the bubbles. In the aeration of low-viscosity, pure liquids such as water, methanol, or acetone, a stable bubble diameter of 3-5 mm results, irrespective of the type of the gas distributor. This state is reached immediately after the tiny primary bubbles leave the area of high shear forces. The generation of fine primary gas bubbles in pure liquids is therefore uneconomical. 

Most of the common alcohols, up to about 11 or 12 carbon atoms, are liquids at room Physical Properties temperature. Methanol and ethanol are free-flowing volatile liquids with characteris-Of AI CO hols c frui y °dors. The higher alcohols (the butanols through the decanols) are somewhat viscous, and some of the highly branched isomers are solids at room temperature. These higher alcohols have heavier but still fruity odors. Propan-1 -ol and propan-2-ol fall in the middle, with a barely noticeable viscosity and a characteristic odor often associated with a physician s office. Table 10-2 lists the physical properties of some common alcohols. 

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