Vapor phase neutralization

Dimeric ion. An ion formed either when a chemical species exists in the vapor phase as a dimer and can be detected as such, or when a molecular ion can attach to a neutral molecule within the ion source to form an ion such as (2M)+, where M represents the molecule. 

Formaldehyde condenses with itself in an aldol-type reaction to yield lower hydroxy aldehydes, hydroxy ketones, and other hydroxy compounds the reaction is autocatalytic and is favored by alkaline conditions. Condensation with various compounds gives methylol (—CH2OH) and methylene (=CH2) derivatives. The former are usually produced under alkaline or neutral conditions, the latter under acidic conditions or in the vapor phase. In the presence of alkahes, aldehydes and ketones containing a-hydrogen atoms undergo aldol reactions with formaldehyde to form mono- and polymethylol derivatives. Acetaldehyde and 4 moles of formaldehyde give pentaerythritol (PE) ... 

Dehydration of 1-pentanol or 2-pentanol to the corresponding olefins has been accompHshed, in high purity and yields, by vapor-phase heterogeneous catalyzed processes using a variety of catalysts including neutral gamma —Al Og catalyst doped with an alkah metal (23), zinc aluminate (24,25), hthiated clays (26), Ca2(P0 2 montmorillonite clays (28). Dehydration of 2-methyl-1-butanol occurs over zinc aluminate catalyst at... 

Processes involving oxygen and nitrogen oxides as catalysts have been operated commercially using either vapor- or Hquid-phase reactors. The vapor-phase reactors require particularly close control because of the wide explosive limit of dimethyl sulfide in oxygen (1—83.5 vol %) plants in operation use Hquid-phase reactions. Figure 2 is a schematic diagram for the Hquid-phase process. The product stream from the reactor is neutralized with aqueous caustic and is vacuum-evaporated, and the DMSO is dried in a distillation column to obtain the product. 

Zinc chloride melts at 275°C, bods at 720°C, and is stable in the vapor phase up to 900°C. It is very hygroscopic, extremely water-soluble, and soluble in organic Hquids such as alcohols, esters, ketones, ethers, amides, and nitrides. Hydrates with 1, 1.5, 2.5, 3, and 4 molecules of water have been identified and great care must be exercised to avoid hydration of the anhydrous form. Aqueous solutions of zinc chloride are acidic (pH = 1.0 for 6 M) and, when partially neutralized, can form slightly soluble basic chlorides, eg, ZnCl2 4Zn(OH)2 [11073-22-6] and Zn(OH)Cl [14031-59-5]. Many other basic chlorides have been reported (58). 

A fundamental functional property of a neutralizing amine (vapor-phase amine) is its volatility. Derived from this function is relative volatility and the DR. 

The primary reason for employing vapor-phase or neutralizing amines in steam-condensate systems is to reduce the level of corrosion of both ferrous and nonferrous metals. A further beneficial consequence of this function is the reduction of metal transported back to the FW system. 

After extraction of the neutral oil from the AOS sample, the neutral oil is made up volumetrically to at least a 10% solution in hexane. Of this solution 4 pi is spotted onto a silica gel TLC plate, together with terminal 5-sultone standard in the range 0.4-4 pg (equivalent to 0.1-1% sultone in the neutral oil). It is twice developed in a chamber saturated with 2-propyl ether. The solvent is completely evaporated and the spots visualized by vapor phase sulfuric acid charring using the technique described by Martin and Allen [139]. Humidity is not critical (10-30% is optimum) and activation of the plates has not been found necessary, but it might be required under conditions of high humidity. The level of sultone can be estimated by visual comparison with the standards or by the use of a densitomer. 

The results here clearly demonstrate some of the important differences between reactions in the vapor phase and those in the aqueous phase. Water solvates the ions that form and thus enhances the heterolytic bond activation processes. This leads to more significant stabilization of the charged transition and product states over the neutral reactant state. The changes that result in the overall energies and the activation barriers of particular elementary steps can also act to alter the reaction selectivity and change the mechanism. 

Neutralization of zinc acceptors in InP by hydrogen occurs also in nonintentionally hydrogenated materials grown by organometallic vapor phase epitaxy (Antell et al., 1988 Cole et al., 1988). Levels of hydrogen comparable to the zinc concentration have been detected by SIMS experi ... 

Neutral Oxides and Sulfides of Carbon, Vapor Phase Photochemistry of the... 

Crystalline indium trihalides are readily prepared from the reaction of the metal and halogen9 (sometimes in the presence of solvent), from metal+ HX, or by the electrochemical oxidation of the metal in a non-aqueous solution of X2.20 Indium trichloride and tribromide have indium octahedrally coordinated by halide in the solid state, whereas the triiodide exists as the dimer I2lnl2InI2 in the solid or in solution all three halides are dimeric in the vapor phase.9 The many adducts of these compounds with neutral donors have been extensively reviewed previously.5,7... 

There is widespread interest (220) in the electronic structures of tetrahedral oxyanions of the type M04. Being quasi-isoelectronic the neutral tetroxides, M04, M = Ru, Os, are well suited for vapor-phase UPS studies (49, 102, 140) of the bonding in this type of system. Unfortunately impurities are apparent in two of these spectral studies (102, 140), and in one of them (140) doubts have been raised (49) about the validity of the reported vibrational fine structure. Furthermore, the interpretations presented in the three papers are somewhat different. Overall, the interpretation of Orchard et al. (49) appears to be the most reasonable. 

The unrestricted form of the primitive model (UPM) becomes important for more complex fluid systems. Stell argued that symmetry breaking in the UPM may play an important role in determining critical behavior [17]. In spite of this potential utility, the UPM is rarely explored. In MC simulations of the cluster structure in the UPM, Camp and Patey [259] compared results for asymmetrical charges Xq = z+/z = 1,2,4 at the diameter ratio Xa = vapor phase contains, above all, neutral clusters such as trimers for Xq — 2 and tetrahedral pentamers for Xq = 4, as well as higher clusters. At Xq = 4 asymmetry effects not covered by simple theories seem to play a role. 

A third dimer was obtained from Norway sprucewood in somewhat impure condition (m.p., 117°-127°C.). However, its vapor phase retention time and ultraviolet spectrum 23) were identical with those of authentic 5,5 -diethyl-2,2 -dihydroxy-3,3 -dimethoxybiphenyl (VII), m.p. = 143°C. (P). Furthermore, the NMR spectrum and melting point of its purified diacetate were identical with those of the synthetic compound. The corresponding 5,5 -di-w-propyl derivative has already been isolated from neutral hydrogenation of softwood lignin in our laboratory 18). 

MALDI A soft (gentle) method for creating gas-phase ions that utilizes energy from a laser targeted onto a mixture of analyte and a chemical matrix. Analyte ions can be formed from a combination of vaporization of existing ions and by vaporization of neutrals followed by ionization in the gas phase (Hillenkamp et al., 1990). 

Radzika, A., Wolfenden, R. (1988) Comparing the polarities of the amino acids Side-chain distribution coefficients between the vapor phase, cyclohexane, 1-octanol and neutral aqueous solution, Biochemistry 27, 1664-1670 ... 

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