NOPR Collection:

An extractive colorimetric method for determination of pentachlorophenol (PCP)

Mon, 01 May 2006 00:00:00 GMT

Title: An extractive colorimetric method for determination of pentachlorophenol (PCP) Authors: Sao, Aruna; Pillai, Ajai K; Gupta, V K Abstract: A new extractive spectrophotometric method, which is sensitive, is described for the determination of pentachlorophenol (PCP), a widely used insecticide and herbicide. The method is based on the reaction of pentachlorophenol with concentrated nitric acid at elevated temperature to form chloranil, which liberates iodine with potassium iodide. The liberated iodine then forms yellow brown coloured complex with cetyltrimethyl-ammoniumbromide (CTAB) having absorption maximum at 390 nm and extractable into isoamyl alcohol. Beer’s law is obeyed over the concentration range of 2.5-20 g of PCP in a final solution 100 mL (0.025-0.20 ppm) and has molar absorptivity and Sandell’s sensitivity values of 9.610⁵ L mol^-1 cm^-1 and 0.000277-gcm^-2, respectively. The detection limit and quantification limit for the proposed method is found to be 0.0018 and 0.0063 ppm, respectively. The method has been satisfactorily applied for the determination of PCP in water, plant material and biological samples. Page(s): 294-297

Prediction of vapour-liquid pseudo-equilibrium data for pervaporation of benzene-cyclohexane system

Mon, 01 May 2006 00:00:00 GMT

Title: Prediction of vapour-liquid pseudo-equilibrium data for pervaporation of benzene-cyclohexane system Authors: Mitra (‘nee Sarkhel), Debarati; Roy, Debashis; Bandyopadhyay, Madhusree; Bhattacharya, Pinaki Abstract: In pervaporation operation pore diffusion model predicts that a vapour-liquid pseudo-equilibrium exists between the solute concentration in vapour and liquid phases during its flow through the pores of the membrane. In the present investigation, using pore diffusion model an attempt has been made to predict a semi-empirical vapour-liquid equilibrium relationship for benzene concentration in vapour and liquid inside the pore of the membrane while separating benzene-cyclohexane azeotropic mixture by pervaporation technique. Page(s): 290-293

Photoinitiated copolymerization of -terpineol and methylmethacrylate

Mon, 01 May 2006 00:00:00 GMT

Title: Photoinitiated copolymerization of -terpineol and methylmethacrylate Authors: Yadav, Sarika; Srivastava, A K Abstract: Free radical copolymerization of a-terpineol and methylmethacrylate (MMA) in xylene at 30±0.2°C using azobisisobutyronitrile (AIBN) as the photoinitiator for 27 h has been carried out. The kinetic expression is {R_p[AIBN]^0.62, [-terpineol]^1.2, [MMA]^1.5}. It is attributed to primary radical termination as well as degradative chain transfer reaction. Analysis of the copolymers by IR and NMR shows the presence of alcoholic and carboxyl group due to acrylate in the copolymer. The glass transition temperature of the copolymer, determined by differential scanning calorimetry, is 85°C. The alternating nature of the copolymer is confirmed by the product of the reactivity ratios r₁ [MMA] = 0.12 and r₂[-terpineol] = 0.08. The Alfrey-Price, Q-e parameter for -terpineol has been calculated as 0.282 and 1.82, respectively. A possible mechanism of the copolymerization has been proposed. Page(s): 283-289

Ternary inhibitor system containing phosphonate, molybdate and Zn²⁺ in corrosion control of carbon steel

Mon, 01 May 2006 00:00:00 GMT

Title: Ternary inhibitor system containing phosphonate, molybdate and Zn²⁺ in corrosion control of carbon steel Authors: Rao, B V Appa; Christina, K Abstract: With the objective of developing a new environmental friendly inhibitor formulation for corrosion of carbon steel in nearly neutral aqueous environments, phosphonic acid viz., N-(2-hydroxyethyl) imino-bis(methylphosphonic acid) [HEIBMPA] was chosen as the inhibitor. Zn²⁺ was chosen as the first synergist. A maximum inhibition efficiency of 99.3% was obtained with the binary system containing 70 ppm HEIBMPA and 80 ppm Zn²⁺. Molybdate ion, which is inorganic in nature but environmental friendly, was used as the second synergist. The binary inhibitor formulation containing relatively low concentrations, viz., 30 ppm HEIBMPA and 40 ppm Zn²⁺ offered an inhibition efficiency of only 23%. To the above combination, when 200 ppm molybdate was added, the inhibition efficiency was found to increase to 95%. The potentiostatic polarization studies revealed that this ternary inhibitor system controlled the anodic reaction predominantly. A large increase in the polarisation resistance (R_p) value indicated the formation of a non-porous protective film on the metal surface. The reflection absorption FT-IR spectrum and X-ray photoelectron spectra of the film suggested that the film consisted of [Fe(III)-HEIBMPA-molybdate] complex, [Fe(III), Zn(II)-HEIBMPA-molybdate]complex, oxides and hydroxides of iron and Zn(OH)₂. A plausible mechanism of inhibition of corrosion is proposed, which explains all the above experimental results. Page(s): 275-282

NOPR Collection:

An extractive colorimetric method for determination of pentachlorophenol (PCP)

Prediction of vapour-liquid pseudo-equilibrium data for pervaporation of benzene-cyclohexane system

Photoinitiated copolymerization of -terpineol and methylmethacrylate

Ternary inhibitor system containing phosphonate, molybdate and Zn2+ in corrosion control of carbon steel

Ternary inhibitor system containing phosphonate, molybdate and Zn²⁺ in corrosion control of carbon steel