Pyrolysis of Methyl Ricinoleate: Distribution and Characteristics of Fast and Slow Pyrolysis Products

Abstract

A stable temperature site and the speed of heating the feedstocks play a key role in pyrolysis processes. In this study, the product distribution arising from pyrolysis of methyl ricinoleate (MR) at 550 °C with low and high heating rates was first studied by pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The results show that fast pyrolysis of MR favored the production of undecylenic acid methyl ester (UAME) and heptanal (HEP). Density functional theory (DFT) calculations were employed to reveal the UAME and HEP formation process from pyrolysis of MR. The bond dissociation energies (BDEs) of C–C bonds in MR showed that the C11–C12 bond is the weakest. This suggests that UAME and HEP are two major products. The process of slow and fast MR pyrolysis was the dehydration-first and the pyrolysis-first trend, respectively. The calculated activation energies of MR pyrolysis to UAME and HEP and MR dehydration to 9,12-octadecadienoic acid methyl ester were 287.72 and 238.29 kJ/mol, respectively. The much higher product yields obtained in the fast pyrolysis reactors than those from conventional tubular reactors confirmed the proposed process.

High Yield Synthesis of Green Pyrolytic Oil via Thermal Cracking of Ricinoleic Acid Methyl Ester

“…Experimental studies and theoretical calculations are performed to investigate the mechanisms involved in the fast pyrolysis of hemicelluloses into short‐chain acids [43] . The calculations provided insights into the probability of bond dissociations occurring in the molecule, the ring opening mechanism, and the energy involved in the cleavage of bonds and helped to comprehend the steps involved in the pyrolysis reaction [27,38–42] …”

“…[43] The calculations provided insights into the probability of bond dissociations occurring in the molecule, the ring opening mechanism, and the energy involved in the cleavage of bonds and helped to comprehend the steps involved in the pyrolysis reaction. [27,[38][39][40][41][42] As a result of previous research, RAME is selected as the model reactant compound, and MU and HEP are selected as the model products from the distribution of thermal cracking products. First principal density functional theory (DFT) calculations are performed for the identification and energy optimization of the reactant and product structures using the DMol3 package in Accelrys Materials Studio.…”

“…Thus, DFT calculations were performed to study the dissociation of reactant RAME into products MU and HEP using the Gaussian09 suite of programs with the B3LYP/Def2-TZVP basis set. [27] Calculations using the RPBE functional Experimental studies and theoretical calculations are performed to investigate the mechanisms involved in the fast pyrolysis of hemicelluloses into short-chain acids have also been performed to study the reaction pathway involved in the pyrolysis of biomass compound cellulose. [38] Calculations with the B3LYP functional were carried out to study the pyrolysis of another biomass compound, viz.…”

“…[16,24,25] Mainly, HEP and MU are essential raw materials used to synthesize and produce valuable organic compounds such as lubricants, cosmetics, pharmaceuticals, and polymeric materials. [16,[25][26][27][28][29][30] MU is widely used in a variety of applications, including medicine, jet fuel, antimicrobials, antibiotics, antitumors, antifungals, and the processing of nylon-11. [14,28,31] Additionally, HEP is an industrial solvent for various polymers and emulsifiers, plasticizers, and insecticide sources.…”

“…The ricinoleic molecule of castor oil splits from the hydroxyl position when exposed to 525 °C, resulting in the formation of HEP and MU [16,24,25] . Mainly, HEP and MU are essential raw materials used to synthesize and produce valuable organic compounds such as lubricants, cosmetics, pharmaceuticals, and polymeric materials [16,25–30] . MU is widely used in a variety of applications, including medicine, jet fuel, antimicrobials, antibiotics, antitumors, antifungals, and the processing of nylon‐11 [14,28,31] .…”