Substituted phenothiaziiies as indicators in the ferrocyanide titration of zinc

Chlorpromazine, promethazine and diethazine hydrochlorides and prochlorperazine maleate have been tested as indicators in the ferrocyanide titration of zinc. Only the first and last are useful, giving a sharp reversible colour change in both the direct and reverse titrations, but the results are negatively biased by 0.2-1.3%.     

Formula for a solution ofu t +H(u,Du) =g

We study the continuous as well as the discontinuous solutions of Hamilton-Jacobi equationu _t +H(u,Du) =g in ℝ ⁿ x ℝ₊ withu(x, 0) =u ₀(x). The HamiltonianH(s,p) is assumed to be convex and positively homogeneous of degree one inp for eachs in ℝ. IfH is non increasing ins, in general, this problem need not admit a continuous viscosity solution. Even in this case we obtain a formula for discontinuous viscosity solutions.     

Performance of miniature resistance strain gages in low-cycle fatigue

Experimental results describing the behavior of five types of miniature resistance strain gages subjected to cyclic strains of high amplitude are presented. Test procedure and instrumentation are described. Changes in zero drift and changes in gage sensitivity are discussed with respect to various strain gage and test variables. Mechanisms of gage failure, effect of variation of imposed strain and hysteresis in gage response are discussed.     

Synthesis of novel β-aryl-β-(methylthio)acroleins via Vilsmeier–Haack protocol as potential 1,3-dielectrophilic three-carbon building blocks

A new general route for the synthesis of novel β-aryl-β-(methylthio)acroleins, a class of stable potential 1,3-dielectrophilic synthons, has been reported. The overall protocol involves treatment of either β-chloroacroleins or their precursor iminium salts (generated in situ from the corresponding active methylene ketones under Vilsmeier–Haack reaction conditions) with S,S-dimethyldithiocarbonates (DDC)/aqueous KOH in either a one-pot or two-step process. The dimethyldithiocarbonate (DDC)/30% aqueous KOH has been shown to be an excellent source of methylthiolate anion.     

A simple and sensitive spectrophotometric method for the determination of trace amounts of nitrite in environmental and biological samples using 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt

A very simple, sensitive, fairly selective and rapid spectrophotometric method for the determination of trace amounts of nitrite has been described. This method is based on the diazotized intramolecular coupling of electrophilic diazonium cation with the phenolic group of 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt (AHNDMS) in a phosphate buffer solution of pH 7.5. The cyclic product has a purple color with maximum absorbance at 560 nm and is stable for 6 h. Optimum reaction conditions and other important analytical parameters for the maximum color development were established. Beer's law was found to obey for nitrite in the concentration range of 0.1–1.6 μg ml^?1 with molar absorptivity of 2.6 × 10⁴ l mol^?1 cm^?1 and Sandell's sensitivity of 0.0075 μg ml^?1. The effect of interfering ions on the determination is described. The recommended method was applied for the determination of nitrite in different water, soil and human saliva samples. The performance of the recommended method was evaluated in terms of Student's t-test and variance ratio F-test, which indicated the significance of proposed method over the reference method.     

N,N′-dichloro-p-nitrobenzenesulfonamide (dichloramine-N) as a new oxidimetric reagent: Synthesis and analytical application

A new oxidimetric reagent, dichloramine-N (N,N′-dichloro-p-nitrobenzenesulfonamide; DCN) has been synthesized and its structure elucidated from the spectral data and elemental analyses. The ultraviolet, infrared, nuclear magnetic resonance, and mass spectral data have been presented. Analytical applications of DCN as a potential redox titrant in the determination of diverse reductants such as ascorbic acid, methionine, sulfite, arsenite, glutathione, and indigocarmine have been described.     

Synthesis and characterization of rhenium(VII) oxide complexes of phenothiazines

Summary Five complexes of rhenium(VII) oxide with N-alkylphenothiazines have been synthesized and characterized on the basis of elemental analyses, molar conductances, and u.v.-vis., i.r. and n.m.r. spectral data. The molecular formulas of the new ionic complexes are: [ReO₃(PTZ)₂(H₂O)][ReO₄], PTZ = chlorpromazine, promethazine or ethopropazine; [ReO₃(TF)(H₂O)][ReO₄], TF = trifluoperazine; and [ReO₃(TR)₃][ReO₄(H₂O)₂]·H₂O, TR = thioridazine. Tentative structures have been proposed.