Water-soluble crystalline substances

Morphine, C17H1903N + HaO.—White amorphous or crystalline substance, sparingly soluble in cold water and in ether soluble in NaOH solution M.P. 230°. 

The chemical category of inorganic salts encompasses many substances that dissociate completely in water, but only one salt, sodium chloride, is referred to by the common name, salt. Sodium chloride is ubiquitous in both its occurrence and its many uses. To date, there are over 14,000 uses for salt.1 Salt is used as a feedstock for many chemicals including chlorine, caustic soda (sodium hydroxide), synthetic soda ash (sodium carbonate), sodium chlorate, sodium sulfate, and metallic sodium. By indirect methods, sodium chloride is also used to produce hydrochloric acid and many other sodium salts. In its natural mineral form, salt may take on some color from some of the trace elements and other salts present, however, pure sodium chloride is a white to colorless crystalline substance, fairly soluble in water.2 Also known as halite, the substance... 

Rubidium nitrite, RbN02.—Barium nitrite and rubidium sulphate interact to form rubidium nitrite, a yellowish, crystalline substance, very soluble in water.2... 

It is a white crystalline substance slightly soluble in water. This compound is of especial interest because it acts both as a weak base and as a weak acid. The metallic salts are the more stable and the most important one is the calcium salt. 

Tellurium trioxide, TeOs, is made by carefully heating H2TeO< to a red heat. It is an orange-yellow crystalline substance, sparingly soluble in water, and easily decomposed by heat, forming the dioxide and oxygen. 

Owing to its lower volatility, ethylmercury phosphate—(CjHjHg)3PO — is less hazardous than ethylmercury chloride. The compound is a white, crystalline substance, readily soluble in water it is therefore mainly used as the active substance in wet seed dressings. 

From the aqueous solution of methoxyethylmercury acetate, methoxyethylmercury chloride (9), a white, crystalline substance slightly soluble in water, is precipitated with sodium chloride ... 

A quinoline derivative, 8-hydroxyquinoline (27) was the first fungicide with systemic properties, but it did not find a wide application. It is a white crystalline substance, slightly soluble in water but readily soluble in alkalies and acids, with the formation of salts. It is of medium toxicity, its acute oral being 1000 mg/kg for... 

The crystalline substance, slightly soluble in water and readily soluble in organic solvents, is a soil herbicide. It is effective against annual grass weeds in sugar beet and legumes at a rate of 6-8 kg/ha. The lDjo for rats is 3000 mg/kg. 

The acid is a crystalline substance, very soluble in water, and has the composition CHO.COOH.H2O. The added water does not appear to be water of crystallization, as the compound can not be decomposed into anhydrous glyoxylic acid and water by heat. When an attempt is made to drive the water out of the compound, complete decomposition results. The structure of the compound, as given above, is not satisfactory, as it leads to a false conception as to its behavior when heated. For this reason the structure sometimes assigned to glyoxylic acid is that represented by the HO ... 

The silver salts of (I) to (IV) are white crystalline substances, sparingly soluble in water and organic solvents, but soluble in aqueous ammonia. The initiating efficiency was determined as the smallest amount of the salt needed for initiation of RDX in tubing of a number 8 detonator. The details of the procedure are reported by Avanesov [7]. The experimental values of the minimal amount increases in the following order ... 

The production of melamine-formaldehyde oligomers uses as raw materials formaldehyde and melamine (2,4,6-triamino-l,3,5-triazine). The latter is a crystalline substance, heavily soluble in water (5% at 100°C), and it shows a stronger alkaline character than urea or formaldehyde. From the very beginning, one should note that melamine-formaldehyde oligomer structure depends strongly on working conditions. 

Properties— PABA is a yellow, crystalline, slightly water-soluble substance. 

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. 

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. 

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. 

This group comprises substances of the tjrpe RCONHR and RCONR R", i.e., substituted amides of the aromatic series. They are all well-defined crystalline sohds, sparingly soluble in cold but, often, appreciably soluble hi hot water and moderately soluble in ether they are generally neutral or feebly basic in reaction. 

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. 

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). 

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. 

Amino acid zwitterions are internal salts and therefore have many of the physical properties associated with salts. They have large dipole moments, are soluble in water but insoluble in hydrocarbons, and are crystalline substances with relatively high melting points. In addition, amino acids are amphiprotic they can react either as acids or as bases, depending on the circumstances. In aqueous acid solution, an amino acid zwitterion is a base that accepts a proton to yield a cation in aqueous base solution, the zwitterion is an add that loses a proton to form an anion. Note that it is the carboxylate, -C02-, that acts as the basic site and accepts a proton in acid solution, and it is the ammonium cation, -NH3+, that acts as the acidic site and donates a proton in base solution. 

In every case, the alkali metal reacts to form a stable, ionic solid in which the alkali is present as an inert gas-like ion. The product is, in each case, a crystalline substance with high solubility in water. 

Sample Preparation. Liquid crystalline phases, i.e. cubic and lamellar phases, were prepared by weighing the components in stoppered test tubes or into glass ampoules (which were flame-sealed). Water soluble substances were added to the system as water solutions. The hydrophobic substances were dissolved in ethanol together with MO, and the ethanol was then removed under reduced pressure. The mixing of water and MO solutions were made at about 40 C, by adding the MO solution dropwise. The samples for the in vivo study were made under aseptic conditions. The tubes and ampoules were allowed to equilibrate for typically five days in the dark at room temperature. The phases formed were examined by visual inspection using crossed polarizers. The compositions for all the samples used in this work are given in Tables II and III. 

As shown in Fig. 2 [37], and also in the work of Barraclough and Hall [34], moisture uptake onto sodium chloride as a function of relative humidity is reversible as long as RH0 is not attained. This is evidence that actual dissolution of water-soluble crystalline substances does not occur below RH0. This is consistent with thermodynamic rationale that dissolution below RHo would require a supersaturated solution (i.e., an increased number of species in solution would be necessary to induce dissolution at a relative humidity below that of the saturated solution, RH0). In this regard, one should only need to consider the solid state properties of a purely crystalline material below RH0. As will be described, other considerations are warranted for a substance that contains amorphous material. 

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