Multivariate study and optimization of biodiesel production using commercial surfactants

Abstract

Alkaline transesterification of vegetable oils or animal fats (apolar substances) with a short-chain alcohol (polar substance) is the best-known chemical route for biodiesel production. However, because they are substances of different polarities, there is a need to promote contact between the phases. Biodiesel was produced from soybean oil, methanol, potassium hydroxide, and surfactants DBB 7104 and DBB 7107. In this paper we verify whether it is better to use surfactant DBB 7104 or DBB 7107, and if there is an optimum experimental condition for the surfactant. The yield in biodiesel was verified for different production conditions on a bench scale. From a fractional experimental plan (2 6-2), with a variation of temperature, time, methanol-to-oil mole ratio, weight of surfactant, type of surfactant and weight of catalyst, it was possible to perform a multivariate analysis of the process. The most influential variables in the response were the temperature and the weight of the catalyst. Surfactant DBB 7107 was considered better than the surfactant DBB 7104. The optimal conditions were 0.7% w/w of the surfactant DBB 7107, 1 g of KOH, 30 min, methanol to oil mole ratio of 6:1 and temperature equal to 33.5 °C.

Effects of the Addition of [2hea][hx] on Biodiesel Synthesis Using Methanol and Methanol/Ethanol Mixture

“…Scientific interest in using traditional organic cosolvents and surfactant is due to the fact that they produce high yields in short period of time and at mild temperatures, even room temperature. Basically, they are intended to reduce the interfacial tension in the mixture (Wu et al, 2016;Simonelli et al, 2018).…”

“…The interfacial behavior of some substances has already been employed to overcome common mass transfer restrictions in transesterification. In some studies, organic surfactants and co-solvents, (e.g., acetone, esters, tetrahydrofuran, and hexane) have been used as additive to increase mixture efficiency, contact and mutual solubility between the immiscible phases and, consequently, improve the reaction rate in the transesterification and yield in biodiesel These organic co-solvents generally are used in high amounts 14.5%-25% (%wt/wt) with reference to the oil mass, additionally, they are toxic, volatile, and generate wastes that are difficult to separate and discard (Alhassan et al, 2014;Encinar et al, 2016;Fadhil et al, 2015;Simonelli et al, 2018;Wu et al, 2016 . This anion was chosen because it has the polar carboxyl and apolar carbon chain, similar to the stearic one proposed by Santos et al (2014), but with a lower carbonic chain and lower viscosity.…”