Substance, crystalline

The amino-acids are colourless, crystalline substances which melt with decomposition. They are mostly soluble in water and insoluble in alcohol. 

NH4][ON(NO)C6Hj]. a reagent originally suggested for use in the detection of Cu but now used for the separation of Fe/Ti and Zr which it precipitates from acid solutions. Cupferron is a brownish-while crystalline substance, soluble in water. 

PPha, pyridine) organic groups (olefines, aromatic derivatives) and also form other derivatives, e.g. halides, hydrides, sulphides, metal cluster compounds Compounds containing clusters of metal atoms linked together by covalent (or co-ordinate) bands, metaldehyde, (C2H40) ( = 4 or 6). A solid crystalline substance, sublimes without melting at I12 1I5" C stable when pure it is readily formed when elhanal is left in the presence of a catalyst at low temperatures, but has unpredictable stability and will revert to the monomer, ft is used for slug control and as a fuel. 

NH2-C0-NH NH2,CH5N30. Colourless crystalline substance m.p. 96" C. Prepared by the electrolytic reduction of nitrourea in 20% sulphuric acid at 10 "C. Forms crystalline salts with acids. Reacts with aldehydes and ketones to give semicarbazones. Used for the isolation and identification of aldehydes and ketones. 

The surface tensions for a certain cubic crystalline substance are 7100 = 160 ergs/cm, 7110 = 140 eigs/cm, and 7210 = 7120 = 140 ergs/cm. Make a Wulff construction and determine the equilibrium shape of the crystal in the xy plane. (If the plane of the paper is the xy plane, then all the ones given are perpendicular to the paper, and the Wulff plot reduces to a two-dimensional one. Also, 7100 = 7010. etc.)... 

If the entropy of each element in some crystalline state be taken as zero at the absolute zero of temperature, every substance has a finite positive entropy, but at the absolute zero of temperature the entropy may become zero, and does so become in the case of perfect crystalline substances. 

In the Lewis and Gibson statement of the third law, the notion of a perfect crystalline substance , while understandable, strays far from the macroscopic logic of classical thennodynamics and some scientists have been reluctant to place this statement in the same category as the first and second laws of thennodynamics. Fowler and Guggenheim (1939), noting drat the first and second laws both state universal limitations on processes that are experunentally possible, have pointed out that the principle of the unattainability of absolute zero, first enunciated by Nemst (1912) expresses a similar universal limitation ... 

A second preparation to illustrate sulphonation is that of sulphanilic acid, NH2C4H4SO3H, a highly crystalline substance which, having a low solubility in cold water, can be readily isolated. If aniline is treated with an excess of concentrated sulphuric acid, aniline hydrogen sulphate is first formed, and... 

Pure phenol is a colourless crystalline substance, having m.p. 43°, and b.p. 182° on exposure to air, it slowly sublimes, and on exposure to light, develops a pink colour. It has a characteristic odour, and a limited solubility in water. Phenol in dilute aqueous solution has strongly antiseptic properties, but the crystalline substance should not be allowed to come in contact with the skin, as it may cause severe blistering. 

The nitrosamines are insoluble in water, and the lower members are liquid at ordinary temperatures. The separation of an oily liquid when an aqueous solution of an amine salt is treated with sodium nitrite is therefore strong evidence that the amine is secondary. Diphenylnitrosoamine is selected as a preparation because it is a crystalline substance and is thus easier to manipulate on a small scale than one of the lower liquid members. For this preparation, a fairly pure (and therefore almost colourless) sample of diphenyl-amine should be used. Technical diphenylamine, which is almost black in colour, should not be employed. 

Filter at the pump, and wash well with water. (Yield, about 20 g.) Recrystallise a portion from hot methylated spirit, reserving the remainder for the following preparation. Benzoin is a very pale yellow (almost colourless) crystalline substance, m.p. 137°. 

Although benzenesulphonyl chloride has for simplicity been used in the above discussion, tolucne-/>- sulphonyl chloride, CHaCeH SO Cl, is more frequently used in the laboratory, owing to its much lower cost, the latter being due in turn to the fact that toluene-p-sulphonyl chloride is a by-product in the commercial preparation of saccharin. Toluene-p sulphonyl chloride is a crystalline substance, of m.p. 68° the finely powdered chloride will, however, usually react readily with amines in the Schotten-Baumann reaction it does not react so readily with alcohols, but the reaction may be promoted considerably by first dissolving the chloride in some inert water-soluble solvent such as acetone. 

Salicin is a colourless crystalline substance, soluble in water. It does not reduce Fehling s solution nor does it give a coloration with ferric chloride. On hydrolysis with emulsin, glucose and salicyl alcohol are produced the former reduces Fehling s solution and the latter gives a violet coloration with ferric chloride. 

Krypton is present in the air to the extent of about 1 ppm. The atmosphere of Mars has been found to contain 0.3 ppm of krypton. Solid krypton is a white crystalline substance with a face-centered cubic structure which is common to all the "rare gases."... 

Mesalamine. Rowasa, Asacol, and Pentasa are trade names for mesalamine [89-57-6] (5-ASA, 5-amino-2-hydroxybenzoic acid). It is a white to pinkish crystalline substance that is slightly soluble in cold water and alcohol, more soluble in hot water, and soluble in hydrochloric acid. It may be prepared by the reduction of y -nitrobenzoic acid with zinc dust and HCl. 

The Wenker process (364), carried out by BASF and various other companies since the end of the 1960s, is a distinct improvement. In this process the hemisulfate of monoethanol amine, a nonvolatile, crystalline substance, is used in place of volatile 2-chloroethylamine for the alkaline cyclisation. The reaction can be carried out under pressure (365). 

Pure D-fmctose is a white, hygroscopic, crystalline substance and should not be confused with the high fmctose com symps (HFCS) which may contain 42—90 wt % fmctose and 23—29% water (8,9). The nonfmctose part of these symps is glucose (dextrose) plus small amounts of glucose oligomers and polymers. Fmctose is highly soluble ia water at 20°C it is 79% soluble, compared with only 47% for glucose and 67% for sucrose. 

Propylthiouracil. This compound is a white, powdery, crystalline substance of starch-like appearance with a bitter taste. It is slightly soluble in water, chloroform, and ethyl ether, sparingly soluble in ethanol, and soluble in aqueous alkaline solutions (53). An extensive compilation of its chemical, spectral, and chromatographic properties is available (43). It is assayed titrimetrically with NaOH (53). 

Antimony pentoxide also reacts with a variety of dihydroxy compounds. Thus pyrocatechol yields a crystalline substance ia which three molecules of the diol are associated with one atom of antimony (52). The configuration of this substance has not been estabUshed, but the foUowiag stmcture seems reasonable ... 

Potassium hydroxide is the principal electrolyte of choice for the above batteries because of its compatibiUty with the various electrodes, good conductivity, and low freezing point temperature. Potassium hydroxide is a white crystalline substance having a mol wt = 56.10 density = 2.044 g/mL, and mp = 360° C (see Potassium compounds). It is hygroscopic and very soluble in water. The most conductive aqueous solution at 25 °C is at 27% KOH, but the conductivity characteristics are relatively flat over a broad range of concentrations. 

A number of complex bismuth halides are weU-known, eg, disodium bismuth pentachloride [66184-10-9] Na2BiCl sodium dibismuth heptachloride [66184-09-6J, NaBi Cl and trisodium bismuth hexachlotide [66114-82-7J, Na BiCl. The acid, hydrogen dibismuth heptachloride tnhydrate [66124-39-9] HBi Cl 3H20, is a crystalline substance, stable at room temperature, that maybe isolated by cooling a solution of BiCl in concentrated hydrochloric acid to 0°C. 

Lower Oxides. A number of hard, refractory suboxides have been prepared either as by-products of elemental boron production (1) or by the reaction of boron and boric acid at high temperatures and pressures (39). It appears that the various oxides represented as B O, B O, B22O2, and B23O2 may all be the same material ia varying degrees of purity. A representative crystalline substance was determined to be rhombohedral boron suboxide, B12O2, usually mixed with traces of boron or B2O3 (39). A study has been made of the mechanical properties of this material, which exhibits a hardness... 

In the presence of an alkali metal hydroxide at about 50°C, chloroform condenses with acetone to give l,l,l-trichloro-2-methyl-2-propanol, [57-15-8] ie, chlorobutanol, chloretone, or acetone—chloroform (9,10). Chlorobutanol is a white crystalline substance with a campborlike odor its sedative, anesthetic, and antiseptic properties have given the compound some importance in the pharmaceutical industry. 

The diffusion, location and interactions of guests in zeolite frameworks has been studied by in-situ Raman spectroscopy and Raman microscopy. For example, the location and orientation of crown ethers used as templates in the synthesis of faujasite polymorphs has been studied in the framework they helped to form [4.297]. Polarized Raman spectra of p-nitroaniline molecules adsorbed in the channels of AIPO4-5 molecular sieves revealed their physical state and orientation - molecules within the channels formed either a phase of head-to-tail chains similar to that in the solid crystalline substance, with a characteristic 0J3 band at 1282 cm , or a second phase, which is characterized by a similarly strong band around 1295 cm . This second phase consisted of weakly interacting molecules in a pseudo-quinonoid state similar to that of molten p-nitroaniline [4.298]. 

Crystalline substance is not rapidly attacked by oxygen, although solutions are air-sensitive the compound is stable to high temperature in the absence of oxygen. 

Dicentrine, CgoHjjOjN. (Items 36, 37, 39, 40 list, pp. 172-3.) This alkaloid crystallises, from ether, alcohol, or ethyl acetate in prisms, m.p. 168-9° [a]i) + 62-1° (CHCI3), and yields well-crystallised salts. It contains two methoxyl groups and yields a monoacetyl derivative, colourless leaflets, m.p. 202°, which is not hydrolysed even by boiling alcoholic potash. 1 The methiodide, B. CH3I. HjO, has m.p. 224°, and according to Manske, yields a methine base, m.p. 158-9°, the methiodide of which with potassium hydroxide solution decomposes into trimethylamine and a crystalline substance, presumably a substituted phenanthrenyl-ethylene, which polymerises on recrystallisation. 

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