Spectroscopic Studies on Reaction between Squalene and Vulcanizing Agents in the Presence and Absence of Zinc-2-Mercaptopyridine-N-Oxide

2004 ◽  
Vol 77 (2) ◽  
pp. 201-213
Author(s):  
C. C. Pierre ◽  
R. N. Datta
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Nmr Spectroscopy ◽  
Carbon Black ◽  
Natural Rubber ◽  
High Performance ◽  
Model Compound ◽  
Spectroscopic Studies ◽  
Reversed Phase ◽  
Zinc Stearate

Abstract Model compound vulcanization in combination with reversed-phase high-performance liquid chromatography and NMR spectroscopy was used to elucidate the reactions of accelerator, sulfur, zinc stearate and zinc-2-mercaptopyridine-N-oxide (ZPNO) in natural rubber vulcanization. Studies of different curing ingredient formulations in squalene have been done to determine the influence of each component during the vulcanization. It was found that 2-mercaptopyridine-N-oxide bridged adducts (R-Sx-Pyr(O)) were formed when squalene was heated in the presence of sulfur, curing ingredients and 2,2′-dithiobis(pyridine-N-oxide) (PyrO-S2-PyrO). Possible interactions of R-Sx-Pyr(O) with carbon black have been proposed.

Model Compound Studies on the Devulcanization of Natural Rubber Using 2,3-Dimethyl-2-Butene

2005 ◽  
Vol 78 (4) ◽  
pp. 572-587 ◽  
Author(s):  
V. V. Rajan ◽  
W. K. Dierkes ◽  
J. W. M. Noordermeer ◽  
R. Joseph
Keyword(s):  
Molecular Weight ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Natural Rubber ◽  
High Performance ◽  
Model Compound ◽  
Zinc Stearate ◽  
Low Molecular Weight ◽  
Second Stage ◽  
Weight Model

Abstract The mechanism of devulcanization of sulfur-vulcanized natural rubber with aromatic disulfides and aliphatic amines has been studied using 2,3-dimethyl-2-butene (C6H12) as a low-molecular weight model compound. First C6H12 was vulcanized with a mixture of sulfur, zinc stearate and N-cyclohexyl-2-benzothiazylsulfenamide (CBS) as accelerator at 140 °C, resulting in a mixture of addition products (C6H11−Sx−C6H11). The compounds were isolated and identified by High Performance Liquid Chromatography (HPLC) with respect to their various sulfur ranks. In a second stage, the vulcanized products were devulcanized using the agents mentioned above at 200 °C. The kinetics and chemistry of the breakdown of the sulfur-bridges were monitored. Both devulcanization agents decompose sulfidic vulcanization products with sulfur ranks equal or higher than 3 quite effectively and with comparable speed. Diphenyldisulfide as devulcanization agent gives rise to a high amount of mono- and disulfidic compounds formed during the devulcanization, hexadecylamine, as devulcanization agent, prevents these lower sulfur ranks from being formed.

Development and Validation of A Reversed Phase-High Performance Liquid Chromatography Method for the Quantitative Estimation of Ramipril Drug Content from Formulated Dosage Form

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Raju Chandra ◽  
Manisha Pant ◽  
Harchan Singh ◽  
Deepak Kumar ◽  
Ashwani Sanghi
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Active Ingredient ◽  
High Performance ◽  
Limit Of Detection ◽  
Quantitative Estimation ◽  
Reversed Phase ◽  
Uv Detector ◽  
Chromatography Method ◽  
Drug Content

A reliable and reproducible reversed-phase high performance liquid chromatography (RP-HPLC) was developed for the quantitative determination of Remipril drug content from marketed bulk tablets. The active ingredient of Remipril separation achieved with C18 column using the methanol water mobile phase in the ratio of 40:60 (v/v). The active ingredient of the drug content quantify with UV detector at 215 nm. The retention time of Remipril is 5.63 min. A good linearity relation (R2=0.999) was obtained between drug concentration and average peak areas. The limit of detection and limit of quantification of the instrument were calculated 0.03 and 0.09 µg/mL, respectively. The accuracy of the method validation was determined 102.72% by recoveries method.

Sign in / Sign up

Export Citation Format

Share Document