Additives presence

Hexaco-ordinated Phosphorus Compounds. - The reaction of PCt with alkylammonium fluorides in the presence of secondary amines gives PF5-amine adducts (132)60. The additional presence of alcohols or phenols leads to the formation of alkoxy- or aroxypenta-f luorophosphates, ROPF -. The PF -amine adducts may also be converted into ROPF - by treatment with alcohols or into ArNHPF -by treatment with primary arylamines. 

Zeolites are structurally related to colorless sodalite, Na4Cl[Al3Si3012], and to deeply colored ultramarines. These have aluminosilicate frameworks that enclose cations but no water molecules (Fig. 16.25). Their special feature is the additional presence of anions in the hollows, e.g. Cl-, S()4, S2, or S. The two last-mentioned species are colored radical ions (green and blue, respectively) that are responsible for the brilliant colors. The best-known representative is the blue mineral lapis lazuli, Na4S (.[Al3Si3012], which is also produced industrially and serves as color pigment. 

The earlier references, which state that this powerful oxidant is stable when pure, but explosive when formed as a layer on metallic potassium [1,2], are not wholly correct [3], because the superoxide is manufactured uneventfully by spraying the molten metal into air to effect oxidation [4], Previous incidents appear to have involved the explosive oxidation of unsuspected traces of mineral oil or solvents [3]. However, mixtures of the superoxide with liquid or solid potassium-sodimn alloys will ignite spontaneously after an induction period of 18 min, but combustion while violent is not explosive [3], The additional presence of water (which reduces the induction period) or hydrocarbon contaminant did produce explosion hazards under various circumstances [5], Contact of liquid potassium with the superoxide gives no obvious reaction below 117°C and a controlled reaction between 117 and 177°C, but an explosive reaction occurs above 177°C. Heating at 100°C/min from IT caused explosion at 208°C [6],... 

The properties of the polycarbonate of bisphenol A are directly related to the structure of the polymer. The molecular stiffness associated with this polycarbonate arises from the presence of the rigid phenyl groups on the molecular chain or backbone of the polymer and the additional presence of two methyl side groups. The transparency of the material arises from the amorphous (noncrystalline) nature of the polymer. A significant crystalline structure is not observed in the polycarbonate of bisphenol A because intermolecular attractions between phenyl groups of neighboring polymer chains in the melt lead to a lack of flexibility of the chains that deters the development of a crystalline structure. 

Hydrogenolytic treatment of ( )-28 in methanol in the presence of 10% Pd/C at room temperature and 15 psi of pressure for 24 h gave the amino alcohol 178 as the only product, the species 177 having only a short lifetime (3 h) and saturation of the pyrrole nucleus proceeded slowly and partially under these conditions but it was facilitated by the additional presence of hydrogen chloride which afforded 2-hydroxymethyl pyrrolizidine 179 in 51% yield (Scheme 24) <1998JOC9279>. 

MTX have also been evaluated as models with modified paracellular permeability and the additional presence of a mucus layer [77, 79, 81],... 

The boiling temperature of propanone, however, is 56°C, whereas that of butane is 0°C. This difference is explained by the additional presence of permanent-dipole/permanent-dipole forces between propanone molecules. 

Lewis acid catalyst is normally required when ammonium polyhalides are used, although recourse does not have to be made to strong acids, such as aluminium trichloride. Bromination and iodination reactions are normally conducted in acetic acid in the presence of zinc chloride [32], but chlorination using the ammonium tetrachloroiodate in acetic acid does not require the additional presence of a Lewis acid [33]. Radical chlorination of toluenes by benzyltrimethylammonium tetrachloroiodate in the presence of AIBN gives mixtures of the mono-and dichloromethylbenzenes [34], Photo-catalysed side-chain chlorination is less successful [35], Radical bromination using the tribromide with AIBN or benzoyl peroxide has also been reported [36, 37],... 

The additional presence of 1-nonanal serves as model for the formation of the linear hydroformylation product of 1-octene and its influence on catalyst solubility. The aldehyde lowers the complex solubility further (Fig. 19) as compared to the mixture with olefln only. 

The reactions of acetylene, including its polymerisation, that occur in the presence of cupric chloride solution have been studied 670) in the (additional) presence of biguanide dihydrochloride. This solution has the unique property of promoting the formation of acetic acid from acetylene. 

In common with other aldehydes or ketones that have hydrogen on the a-carbon, enoMzation is possible (see Section 10.1), especially when sugars are treated with base. The additional presence of a hydroxyl... 

This technique has been recently applied in different studies. One of them evaluated the environmental conditions in the treasure rooms of Reims Cathedral, where silver sensors were exposed during a five-year period [306]. The reduction curves point out that the results strongly depend on whether the coupons were displayed inside or outside a case. Regarding the nature of the products developed on the surface during the exposure, only silver sulphide has been found on the coupons kept inside the showcase, while the additional peak found with coupons exposed outside the case suggests the additional presence of silver chloride (see Fig. 6.4a). Moreover,... 

Addition of a primary alkyl group to enolizable ketones can be performed using magne-sium-ate complexes . The additional presence of 2,2 -bipyridyl (1 equiv.) in the reaction mixture improves the yields. The ate complexes are prepared in situ from the corresponding Grignard reagents and alkyllithium compounds (equations 140 and 141). 

When a nitrile is reacted with an aromatic compound in the presence of HC1, in the additional presence of ZnC or AICI3, a ketimine salt is formed, which after subsequent hydrolysis gives an aromatic ketone ... 

A series of adducts of organocadmium halides with neutral bidentate ligands RCdX L (L = dioxane, bipy or phen) have been prepared by electrochemical oxidation of the metal in the presence of L and the alkyl halide. In the additional presence of [N(n-propyl)4]X, salts of the [RCdX2] anion may be isolated.1064... 

Electron donation from the l7tg orbital of the C02 to a metal should result in classical Lewis acid/Lewis base complexes. The poor natural Lewis basicity of C02 usually requires the additional presence of an electron donating group (E) for stable complex formation, e.g. equation (12). In such molecules the integrity of the C02 is lost and such complexes are to be found elsewhere in this publication. 

Asinger s studies demonstrated that product formation is sensitive to the ratio of sulfur to ketone (1), the structure of the ketone, the replacement of ammonia by amines, the temperature and the medium. Room temperature (20-25 °C) reactions in which the ratio of sulfur to ketones is 0.5 favors the formation of 3-thiazoline, 2, as shown in Figure 1. The formation of 5-alkylidene-3-thiazolines, 3, sometimes competes with the formation of 3-thiazolines such is the case when aryl ketones such as l-phenylpropan-2-one and l-phenylbutan-2-one are employed (4). Also the additional presence of hydrogen sulfide promotes the generation of 1,2,4-trithiolanes and 1,2,4,5-tetrathiolanes from ketones ana aldehydes at the expense of 3-thiazoline formation (11-12). Increasing the S/ketone ratio to 8 favors the formation of the 3-imidazoline-5-thione (5), a product which has a greater tendency to result from aryl methyl ketones (3). 

The structure of the interfacial layers in food colloids can be quite complex as these are usually comprised of mixtures of a variety of surfactants and all are probably at least partly adsorbed at interfaces which even individually, can form complex adsorption layers. The layers can be viscoelastic. Phospholipids form multi-lamellar structures at the interface and proteins, such as casein, can adsorb in a variety of conformations [78]. Lecithins not only adsorb also at interfaces, but can affect the conformations of adsorbed casein. The situation in food emulsions can be complicated further by the additional presence of solid particles. For example, the fat droplets in homogenized milk are surrounded by a membrane that contains phospholipid, protein and semi-solid casein micelles [78,816], Similarly, the oil droplets in mayonnaise are partly coated with granular particles formed from the phospho and lipo-protein components of egg yolk [78]. Finally, the phospholipids can also interact with proteins and lecithins to form independent vesicles [78], thus creating an additional dispersed phase. 

Considerable variation in the amount of transverse and longitudinal parenchyma exists among hardwood species. For example, basswood has approximately the same as softwoods, that is about 10%, while some oak species approach k0% parenchyma. As in softwoods, the parenchyma are usually brick-shaped cells although some variations of this shape occurs. The rays, composed of transverse parenchyma, range from one to thirty-plus cells wide. The ray illustrated in Figure 18 is seven cells wide. Thus the higher parenchyma volume is due to wider rays and the additional presence of axial parenchyma which is rather rare in softwood species. 

If the abundances of the entire ethanol contracted spectrum are lowered — keeping their relative heights the same as in the reference spectrum — a point is reached where none of the unknown ions is of lower abundance than the corresponding ethanol peaks. In the example shown in Figure 7, this occurs when the mass 46 ions become the same height. If a measurement reproducibility of 20% is assumed, two other ions (m/e 43 and 45) are found to agree with the abundances required by the ethanol reference spectrum because they fall within the prescribed tolerance window. In this example, the mixture was about 50% ethanol the excess intensities at m/e 31 and 32 were due to methanol and the excess intensity at m/e 44 was due to the additional presence of CO2. 

The elastic bending modulus Kc for lipid bilayers was found to be of the order of 10 x 10-20 J.6 For the lyotropic lamellar liquid crystals, the additional presence of a cosurfactant at the interface shouldleadto smaller values. Various experimental measurements21 provided values ranging between 0.08 and 5 x 10-20 J. 

The magnetic resonance spectrum of HF was studied some nine years earlier than the electric resonance spectrum by Baker, Nelson, Leavitt and Ramsey [93] in this case the transitions studied were magnetic dipole, corresponding to reorientation of the proton and fluorine nuclear spins. Values of the nuclear spin rotation and dipolar constants were essentially confirmed by the later electric resonance measurements. We now describe measurements of the electric resonance spectrum in the additional presence of a strong magnetic field, carried out by de Leeuw and Dymanus [89]. 

Although the use of split-valence basis functions introduces larger flexibility, this may be further increased by the addition of so-called polarization functions, which consist of five or six 3d orbitals for elements of the second row of the periodic table and of three 2p orbitals for hydrogen. The first case is marked by the addition of one asterisk, i.e. 6-31G 194. Two asterisks, i.e. 6-31G 194 or 6-311G 193, indicate the additional presence of polarization 2p orbitals on hydrogens. 

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