Theoretical study on the mechanism and kinetics for the ozonolysis of vinyl propionate

First-Generation Products of Trans-2-Hexenal Ozonolyis: A New Look at the Mechanism

The ozonolysis reaction of trans-2-hexenal was studied theoretically on the basis of highly accurate CCSD(T)-F12b/AVTZ energy values obtained in M06-2X/AVTZ preoptimized nuclear configurations. The kinetics was modeled with the help of the master equation solver MESMER. Apart from the expected stable oxidation products 1-butanal (17%) and glyoxal (35%), a secondary ozonide is formed on the glyoxal channel, which is the principal first-generation product (49%). It is further shown that glyoxal is created on two competing pathways, one of which leads to simultaneous production of the ester propylformate (18%). The inclusion of all of these mechanisms explains the experimental findings and identifies for the first time the origin of the experimental carbon deficit.

Jatropha Oil as a Substituent for Palm Oil in Biobased Polyurethane

Polyurethanes (PUs) are unique polymers that can be tailored to suit certain applications and are increasingly used in many industrial fields. Petrochemicals are still used as the main compound to synthesize PUs. Today, environmental concerns arise in the research and technology innovations in developing PUs, especially from vegetable polyols which are having an upsurge. These are driven by the uncertainty and fluctuations of petroleum crude oil price and availability. Jatropha has become a promising substituent to palm oil so as to reduce the competition of food and nonfood in utilizing this natural resource. Apart from that, jatropha will solve the problem related to the European banning of palm oil. Herein, we review the literature on the synthesis of PUs using different vegetable oils and compare it with jatropha oil and its nanocomposites reinforced with cellulose nanocrystals. Given the potential of vegetable oil PUs in many industrial applications, we expect that they will increase commercial interest and scientific research to bring these materials to the market soon.

Mechanisms and Kinetic Parameters for the Gas-Phase Reactions of 3-Methyl-3-buten-2-one and 3-Methyl-3-penten-2-one with Ozone

Ozonolysis of unsaturated ketones is a common atmospheric chemical process that plays a significant role in controlling the atmospheric budget of OH and O₃, organic acids, and secondary organic aerosols (SOA). In this work, the detailed reaction mechanism and rate coefficients for the reactions of O₃ with two unsaturated ketones, 3-methyl-3-buten-2-one (MBO332) and 3-methyl-3-penten-2-one (MPO332), were investigated by using density functional theory (DFT) and Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The results indicate that the major products are butanedione and formaldehyde for MBO332, and butanedione and acetaldehyde for MPO332. Possible reaction mechanism and thermodynamic parameters of some complex stable Criegee intermediates (SCIs) RR'COO were also be investigated in this study. Some organic peroxides can be regarded as the main products for the further reactions of SCIs. The rate constants calculated with O₃ are 2.59 × 10^-16 cm³ molecule^-1 s^-1 and 2.28 × 10^-16 cm³ molecule^-1 s^-1 for MBO332 and MPO332 at 298 K and 1 atm. The total rate constant is negatively correlated with temperature (200-400 K) and positively correlated with pressure. The atmospheric half-lives of MBO332 and MPO332 based on O₃ are estimated.