Insolubility in Solvents

Metal surfaces show a so-called inert behavior towards adhesives and solvents, that is, neither dissolving nor diffusion processes take place. This property requires a delimitation towards adhesives used for bonding of thermoplastics according to the diffusion bonding principle (Section 9.2.5). 

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Inorg nic Colora.nts. In addition to various white pigments, other inorganic colorants such as those Hsted in Table 9 are used in a number of cosmetic products. These usually exhibit excellent lightfastness and are completely insoluble in solvents and water. 

Nitration of cellulose followed by plasticisation of the product with camphor has the effect of reducing the orderly close packing of the cellulose molecules. Hence whereas cellulose is insoluble in solvents, except in certain cases where there is chemical reaction, celluloid is soluble in solvents such as acetone and amyl acetate. In addition the camphor present may be dissolved out by chloroform and similar solvents which do not dissolve the cellulose nitrate. 

Because of high interchain bonding, cellulose is insoluble in solvents and is incapable of flow on heating, the degradation temperature being reached before the material starts to flow. It is thus somewhat intractable in its native form. Cellulose, however, may be chemically treated so that the modified products may... 

The fluids have reasonably good chemical resistance but are attacked by concentrated mineral acids and alkalis. They are soluble in aliphatic, aromatic and chlorinated hydrocarbons, which is to be expected from the low solubility parameter of 14.9 MPa. They are insoluble in solvents of higher solubility parameter such as acetone, ethylene glycol and water. They are themselves very poor solvents. Some physical properties of the dimethylsilicone fluids are summarised in Table 29.2. 

The phthalocyanines, naphthalocyanines, and certain of their metal derivatives (Figure 6.17) are infrared fluorophores. 61"64 As a class, they are exceptionally stable compounds, with copper (Cu) phthalocyanine (not a fluorophore) remaining intact above 300 °C in air. First used for textile dyeing in the last century and still widely used, there is a rich chemistry of phthalocyanines. Most derivatives can be made by prolonged heating of a phthalimide or phthalic acid derivative with a metal in powder or salt form at elevated temperature. Several derivatives absorb in the near-IR, and either fluoresce or phosphoresce. The electronic transitions of phthalocyanines are complex and have been extensively studied, at least in part because the symmetry of the molecule makes theoretical calculations of its spectroscopic behavior more tractable. Unsubstituted phthalocyanines and naphthalocyanines are, as a class, very insoluble in solvents other than, for instance, nitrobenzene. Sulfonated phthalocyanines are water soluble and exhibit spectra comparable to the parent derivative. Photolumines-cent phthalocyanines (Pcs) include SiPc, ZnPc, and PC itself. These compounds have been little used for practical infrared fluorometry to date however, Diatron Corpora-... 

The rubber loses its original tackiness and becomes insoluble in solvents and is more resistant to deterioration and degradation effects of heat, light and ageing process. 

Heterogeneous solid materials such as silica play an important role in organic synthesis because they provide suitable environments such as appropriately sized cavities for certain reactions, and they work as catalysts [119-122], They usually have high (especially thermal) stability. Their insolubility in solvents facilitates separation of the catalyst from the reaction mixture. 

Reichert and Mathias prepared related branched aramids, to those of Kim,t5-34] from 3,5-dibromoaniline (23) under Pd-catalyzed carbonylation conditions (Scheme 6.7). These brominated hyperbranched materials (24) were insoluble in solvents such as DMF, DMAc, and NMP, in contrast to the polyamine and polycarboxylic acid terminated polymers that Kim synthesized, which were soluble. This supports the observation that surface functionality plays a major role in determining the physical properties of hyperbranched and dendritic macromolecules J4,36 A high degree of cross-linking could also significantly effect solubility. When a four-directional core was incorporated into the polymerization via tetrakis(4-iodophenyl)adamantanc,1371 the resultant hyperbranched polybromide (e.g., 25) possessed enhanced solubility in the above solvents, possibly as a result of the disruption of crystallinity and increased porosity. 

Such fibers should have the same properties as good IRE, e.g. sufficient transmission for IR radiation, insolubility in solvents, and chemical inertness. Further, they should have good mechanical properties (e.g. flexibility), they must be step index fibers, and it must be possible to remove the original cladding and to apply the sensitive one without any damage to the fiber. 

As a class, carbon blacks are insoluble in solvents, stable to acids and alkalies, and have excellent light-fastness. They are used as coloring pigments in all types of decorative and industrial paints. 

The peptide AC-A-S-A-S-A-S-A-S-A-S-C-NH2 was obtained from Ac-A-S-A-Oxa-A-S-A-Oxa-A-S-C-NH2 by treatment with 10% TfOH in TFA for 4.5 h. The soln was then concentrated in vacuo, and the product was precipitated with dry Et20 then washed three times with Et20. Characterization of peptide Ac-A-S-A-S-A-S-A-S-A-S-C-NHj was rendered extremely difficult due to its insolubility in solvents other than TFA and HFIP. 

The AC o polymers are resistant to oxidation in air and remain intact in solvents like toluene [11], This is in contrast to all other known alkali fullerides, including the fee high temperature AC o phases, which rapidly degrade in air. The air stability facilitates experimentation and the stability and the insolubility in solvents provides a mean for separating the polymer phase from other phases. Doping pure with precisely weighed amounts of alkalis at high temperatures is the usual synthesis of AQg compounds with A = K, Rb, Cs. The exact stoichiometry is hard to achieve and most early data are on mixtures of different phases. 

Aside from the well-known trihalides, BXg, the structures of only B2F4 (71), B2CI4 (S), and B4CI4 (1,2) are established. At least three more halides (7S, 72) (BClo. ), soluble in organic solvents (BClo.g), insoluble in solvents and a probably two-dimensional polymer, (BCl) , have been... 

All esterification processes with acetic anhydride yield the fully esterified ester as the first soluble product. If the reaction medium is a solvent for the triester a solution is obtained, and if a reaction which retains the fiber structure is employed, samples taken at intervals are all insoluble in solvents until complete esterification is attained. The process in this way differs from nitration, in which soluble, partially esterified products are obtained by adjustment of the concentration of the nitration acids. In the etherification of cellulose, the ethers (e.g., methylated cellulose) prepared by partial substitution are also soluble products, exhibiting continuous, gradual changes in solubility characteristics with increasing substitution. 

Two very important points about the cathodic behavior of need to be mentioned. First, Cgo anions appear to be stable on the voltammetric time scale, but when electrogenerated by controlled potential coulometry in solution, only the mono- through tetra-anions are stable [6b,6e]. Second, although neutral C o may be insoluble in solvents such as dimethylformamide (DMF), acetonitrile, or tetrahydrofuran (THF), its anions dissolve readily. Therefore, these anions can be generated from a suspension of Cgo [12]. 

Asymmetric anionic polymerization can convert trichloroacetaldehyde (chloral) to a one-handed helical, isotactic polymer (44) having a 4/1-helical conformation with high optical activity ([oi]d +4000° in film).28114-118 Anionic initiators such as 45,115 46,115 and 47117 and Li salts of optically active carboxylic acids or alcohols are used for the polymerization. Although the polymers are insoluble in solvents and their conformation in solution cannot be directly... 

Dinltrogen tetroxide-Boron trifluoride, Nj04 BF3. Prepared by passing BF3 gas into a solution of dinitrogen tetroxide in nitromethane at 0°, it is an amorphous white solid insoluble in solvents with which it does not react. Stirred with benzene for a week, it affords nitrobenzene in 39% yield. It differs from nitric acid in the isomer distribution (o-substitution favored), but the record of yields is far from impressive. G. B. Bachman, H. Feuer, B. R. Bluestein, and C. M. Vogt, Am. Soc., 77,6188 (1955)... 

Polymers that are insoluble in solvents may be dry ashed in the presence of metal retaining agents (e.g. para-toluene sulphonic acid, PTS A) and the ash residue dissolved in 0.1M HC1... 

Because of the metals insolubility in solvents, rubber-metal joints can only be produced with solvent-free reactive adhesives or even contact adhesives after suitable pretreatment. In the case of rubber-metal joints used as shock-absorber, respectively, oscillating elements in car manufacturing, the development of the bonded joint occurs during vulcanization. The term vulcanization dates back to the method developed by Goodyear around 1840 for the crosslinking of natural rubber with the simultaneous impact of sulfur and heat, which were known as byproducts of the volcanism . 

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