Mild Approach for Non‐Catalytic Hydrogenation of Liquid Natural Rubber Using 2,4,6‐Trimethylbenzenesulfonyl Hydrazide as the Diimide Source

Abstract

This article reports an efficient, mild-temperature method for the hydrogenation of liquid natural rubber (LNR). The hydrogenation of LNR was studied using diimide generated in situ from the thermolysis of 2,4,6-trimethylbenzenesulfonyl hydrazide (MSH) in o-xylene at 100 C. The effects of reaction temperature, reaction time, solvent, and MSH/LNR weight ratio on the percentage of hydrogenation were evaluated. 1 H NMR analysis revealed that~80% hydrogenation was achieved with a weight ratio of MSH: LNR = 1:1 at 100 C in o-xylene within 60 min.

Hydrogenation of Liquid Natural Rubber Using 2,4,6-Trimethylbenzenesulfonylhydrazide : Optimisation of Reaction Parameters via Response Surface Methodology

“…Rasid et al had achieved the ratio of 1:1 for optimum MSH:LNR weight ratio. 22 Rasid et al also conducted an experiment with weight ratio of 2:1. It was revealed that the hydrogenation percentage had decreased.…”

“…In addition, Rasid et al (2016) found that 100 ºC was the optimum reaction temperature in order to achieve a high percentage of hydrogenation. 22 During the experiments, the mixing speed was fixed at 650 rpm. Based on the studies that have been done, the range of each parameter was selected.…”

“…Based on the studies that have been done, the range of each parameter was selected. 22 Table 1 shows the variables based on the range of parameters that have been selected in terms of coded actual values.…”

“…20,21 Rasid et al successfully reported the hydrogenation of LNR using 2,4,6trimethylbenzenesulfonylhydrazide (MSH) with slightly milder conditions compared to using TSH. 22 Basically, they have studied the main reaction parameters such as weight ratio of diimide source to LNR, reaction temperature and reaction time.…”

In Situ Hydrogenation of Liquid Epoxidized Natural Rubber Using Diimide

“…Catalytic hydrogenation requires high pressure autoclave and the presence of transition metal catalyst systems such as nickel, titanium, rhodium, ruthenium or palladium [8 -11]. On the other hand, non-catalytic hydrogenation method is more convenient because it only requires a simple apparatus preparation at atmospheric pressure and employed diimide intermediate from thermal decomposition of arylsulfonyl hydrazide [12]. Mahittikul et al reported an in situ hydrogenated natural rubber latex via thermolysis of p-toluenesulfonyl hydrazide (TSH) [13].…”