Picric acid molecular weight

Place a mixture of 0-5 g. of finely powdered thiourea, 0-5 g. of the alkyl halide and 5 ml. of alcohol in a test-tube or small flask equipped with a reflux condenser. Reflux the mixture for a j)eriod depending upon the nature of the halide primary alkyl bromides and iodides, 10-20 minutes (according to the molecular weight) secondary alkyl bromides or iodides, 2-3 hours alkyl chlorides, 3-5 hours polymethy lene dibromides or di-iodides, 20-50 minutes. Then add 0 5 g. of picric acid, boil until a clear solution is obtained, and cool. If no precipitate is obtained, add a few drops of water. RecrystaUise the resulting S-alkyl-iso-thiuronium picrate from alcohol. 

An alternative description of protein-containing RMs was given by Levashov et al. [148] from ultra-centrifugation studies. Water-soluble dyes (picric acid) were used to determine the molecular weights and sedimentation behavior of the non-protein-containing and protein-containing RMs. The proposed model involved two regimes of Wg (i) at low Wg (where the inner reverse micellar diameter was less than the protein diameter), the protein created a new RM around itself such that the volume of the inner cavity of the filled RM was essentially the volume of the solubihzed protein and (ii) at water contents where... 

Nitro compounds, labelled with carbon-14, have been used during the polymerization of styrene (40). It has been shown that picric acid, which is rather an inefficient inhibitor, formally resembles p benzoquinone with this monomer. It becomes incorporated in the polymer but most of it is included in polystyrene of comparatively low molecular weight. Most of the combined picric add can subsequently be removed by treatment with trifluoro-acetic anhydride reagent, showing that the picric acid is not held in the polymer by carbon-carbon bonds. Further, it was shown, by isotope dilution analysis, that most of the picric add removed from the polymer by this treatment appeared as the add. 

Using the same toluene-benzoyl peroxide system Nakatsuka (105) measured polymerization rate and molecular weight as functions of temperature (40° and 58°) and of the concentration of.three retarders p-nitrophenol, 2,4-dinitrophenol and picric acid. Results were consistent with a kinetic scheme postulating (among other things) bimolecular initiation involving peroxide and monomer and spontaneous unimolecular termination of growing polymer chains. 

Introduction. Proteins are substances produced by living matter which on enzymatic or acid hydrolysis yield amino acids. They are non-volatile and of high molecular weight, and form colloidal dispersions from which they may be precipitated by-heat, alcohol, various salts, and acids (tannic, picric, and phosphotungstic). Each protein has a minimum solubility at a characteristic pH which is called the iso-electric point. At this point the protein molecules exist as a regates and the solution has the maximum turbidity. The nature of the union of various amino acids in the protein molecule is not known. One theory assumes that the carboxyl of one amino acid unites with the amino group of another, thus ... 

In dyeing processes, from a practical standpoint, a certain quantity of dyestuff, seldom exceeding two per cent, of the weight of the fibre, is found necessary to produce a maximum effect as far as shade is concerned. But this by no means exjpresses the limit to the amount of dyestuff which may be taken up by the fibre, as Knecht has found that wool is capable of extracting far larger quantities from concentrated dye-baths. If a calculation be made based on the amount of picric acid which is taken up by the fibre, it is found that the maximum amounts of naphthol yellow S, tartrazirie, and crystal violet which may be combined with wool closely approximate to molecular quantities. 

Picric acid, Trinitrophenol, C6H2(N02)3 OH Molecular weight 229.11 specific gravity 1.767 melting point ... 

Picric acid and the picrate salts of amines absorb at 380 nm with a molar absorptivity of 13,400. An accuracy of +2% was obtained for the spectrophotometric determination of molecular weights of amines [30]. Molecular-weight determinations have been reported of sugars from the absorption spectra of their osazones... 

Various immunogenic substances requiring association with carriers are listed in Table 2. Picric acid, discussed as an exceptional low molecular weight sensitizer in Sect. C.II.l, may be cited with some confidence as a compound which associates with autologous carriers, giving rise to an immunogenic complex. This may be inferred from the cross-reactivity data already mentioned, namely that reactions in contact-sensitized animals may only be evoked by contact application of picryl chloride, not by intradermal application or by means of picrylated protein. 

Fig. 4. Graphical and schematic illustrations of thermal unfolding process, (a) Variations in relative sizes of polymer 3 with and without picric acid. Apparent molecular weight obtained relative to polystyrene standards, (b) polymer 3, and (c) polymer 3 with picric acid. Picric acid was introduced as component of elution solvent, 1.0 x 10 M.

Sloneker, J. H., J. B. Mooberry, P. R. Schmidt, J. E. Pittsley, P. R. Watson, A. Jeanes, Spectrophotometric determination of high molecular weight quaternary ammonium cations with picric acid application to residual amounts in polysaccharides. Anal. Chem., 1965, 37, 243-246. 

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