A Comparative Study on Optimization of Reaction Conditions towards Synthesis of Hydroxypropyl Guar Gum with Higher Viscosity and Hydroxypropyl Content: A Statistical Approach

Effect of four reaction factors including reaction time, concentration of NaOH, propylene oxide, and composition (methanol : water, v/v) of reaction medium was determined on hydroxypropyl content (%) and viscosity of hydroxypropyl guar gum using orthogonal design of experiment. Among all synthesized hydroxypropyl guar gum derivatives highest viscosity, and hydroxypropyl content was determined 5708.0 cPs and 0.487% respectively. Taguchi L9 (3⁴) design of experiment suggested 3 h and 0.1 mol as optimized reaction duration and concentration of etherifying reagent for higher hydroxypropyl content as well as viscosity. Optimized amount of NaOH was determined 0.03 and 0.02 mol for hydroxypropyl content and viscosity respectively. While the optimized composition of reaction medium (methanol : water, v/v) was determined 7 : 1 and 9 : 1 for hydroxypropyl content and viscosity respectively. Reaction time, and concentration of propylene oxide were determined as most impacting factor for hydroxypropyl content and viscosity of hydroxypropyl content respectively. Optimized products determined to exhibit 0.83% and 5902 cPs of hydroxypropyl content and viscosity respectively.