Cryoscopic method

Correction for boiling point, 59 Creatine, 132 -Cresol, 164 Cryoscopic method, 32 Crystallisation, 52 Cuprous chloride, 166 Cyclohexanol, 181... 

During the study of the reaction products between six different co-lactams and triethylborane, monomeric (for 36, 39), dimeric (for 38), tetrameric (for 40) and oligomeric (for 35) species have been detected in solution by cryoscopic methods. For 37 [X = -CH2)5-] only lateral reaction products could be observed (Fig. 14) [66]. 

Determination of EGDN in Mixtures with NG by Means of the Refractometer. At the time (1927) of investigation by Mr Rinkenbach of properties of EGDN, there was no accurate method for its detection in mixtures with NG. The cryoscopic method developed in 1920 by M. Manjueyfol E. Guutal, Bull( Fr) 27, 443, was in die opinion of Rinkenbach, while fairly accurate for mixtures of the pure substances, yielded very erroneous results when applied to mixtures extracted from commercial... 

Vapor phase chromatography was used to analyze allylic oxidation products. The column, inch X 35 feet, was packed with 20% UCON 5100 on Celite (50-70). NMR analyses were performed using a Varian A-60 instrument. Molecular weights were determined by cryoscopic methods (benzene and acetic acid solvents). Organoselenium compounds were analyzed for selenium by the method of Gould (2), which involves wet digestion of the sample, followed by iodometric titration of the selenium dioxide produced. 

From molecular weight determinations by cryoscopic methods, the esters of dithioformic acid appear to have a trimeric constitution, for example, (II.CS2Me)3, and it is suggested 3 that the molecule of the acid is similarly constituted and possesses a cyclic structure with alternating carbon and sulphur atoms. 

Several simple, accurate cryoscopic methods have been developed to measure the percentage of lactose hydrolyzed in whey and lactose solutions. Zarb and Hourigan (1979) have developed a novel method combining enzymatic treatment and cryoscopy for the measurement of lactose in milk and milk products. 

Henningson, R. W. 1970. Regulatory agency acceptance of the interpretation of the freezing point value of milk as part of the official cryoscopic method. J. Assoc. Offic. Anal. Chem. 53, 539-542. 

Cryoscopic Method. This is a method of determining the molecular weight (mw) of an organic substance by accurate determination... 

The cryoscopic method is also applicable to other triarylmethyl systems, to some diarymethyl and allylic ions, and, when ortho substituents are present, to aryl acylium ions (20) (Equation 5.15) 73 unfortunately, side reactions frustrate most attempts to generate carbocations in sulfuric acid. 

Solution of the blue iodine cation in oleum has been reinvestigated779 by conductometric, spectrophotometric, and cryoscopic methods confirming the formation of I2+. In 65% oleum, iodine is oxidized to I2+ [Eq. (4.192)]. 

Among the main difficulties with electron crystallography are (1) sample damage from the electron beam (a 0.1-A wave carries a lot of energy), (2) low contrast between the solvent and the object under study, and (3) weak diffraction from the necessarily very thin arrays that can be studied by this method. Despite these obstacles, cryoscopic methods (Chapter 3, Section V) and image processing techniques have made electron crystallography a powerful probe of macromolecular structure, especially for membrane proteins, many of which resist crystallization. 

Dennis and Patnode167 assumed the existence of trimethylgermanol, but neither they nor Schmidt and Ruidisch371 succeeded in isolating it. Schmidt and Ruidisch used titrimetric and cryoscopic methods to show that Me3GeCl was hydrolyzed by water to Me3GeOH,... 

CR, cryoscopic method DV, diffusion constant and intrinsic viscosity EB, ebullioscopic method EG, end-group titration IV, intrinsic viscosity-molecular weight relationship in other solvents LS, light scattering MV, melt viscosity-molecular weight relationship OS, osmotic pressure PR, analysis of polymerization rate SD, sedimentation and diffusion constants SE, sedimentation equilibrium (Archibald s method) SV, sedimentation constant and intrinsic viscosity [see Eq. (72)]. 

Properties.—Phosphoryl bromide is a solid which crystallises in colourless plates. The formula was established by analysis and vapour density.8 The molecular weight as determined by the cryoscopic method is 300 in benzene.9 The density of the solid is given as 2-822.10 The melting-point is given as 45° C.,11 56° C.12 The boiling-point is 193° C. (758 mm.)13 or 198° C. (760 mm.).7 As would be expected, the heat of formation from its elements is considerably less than that of POCl3, and is given by the equation... 

The products of hydrogenation are dimeric as evidenced by cryoscopic methods of determination of molecular weight and X-ray analysis [57]. Different hydrido complexes may be obtained by the reactions [246]... 

Sodium hyposulphite dihydrate forms colourless vitreous prisms, readily soluble in water. On heating it loses its water of crystallization, melts at red heat, and burns with a blue flame, evolving sulphur dioxide. On addition of acid in small proportion the solution develops a red colour, due to separation of sulphur. Molecular-weight determinations by the cryoscopic method indicate it to be the salt of a dibasic acid, and to be represented by the formula Na2S204.4... 

Sodium hyponitrite is readily soluble in water, the concentrated solution being stable in presence of a large proportion of sodium hydroxide. On crystallization the salt is deposited as pentahydrate, this substance losing its water of crystallization in a desiccator or on exposure to air. The anhydrous salt is the more stable form it melts with decomposition at 300° C. The cryoscopic method gives the double molecular formula, Na2N202. 

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