The Research Of Rearrangement Mechanism To Monoterpenes In Acidity

The Monoterpenes is a kind of compounds base on isoprene. Emission inventories showthat it is the most prominent non-methyl compounds. The emission of monoterpenes is huge.Their structures are varied. Most of monoterpenes have one or more double bond, so they canreacted easily in the atmosphere. They are considered to be the formed precursor of ozone andsecondary organic aerosol(SOA). SOA not only influence the air visib, but also affect humanhealthy. The oxidate reaction of monoterpenes is the main process of forming secondaryorganic aerosol.This paper is modeling of about a series of monoterpenes (Limonene，α-Phellandrene，α-Terpinene，α-Pinene，β-Pinene，γ-Terpinene，3-Carene). All electronic structures calculationwere carried out using Gaussian-09programs at Density Functional Theory (DFT) atB3LYP/6-311+G(2df,2P) and G3MP2with solution effect. We research the mechanism ofrearrangement of monoterpenes in acidity, and we get some valuable conclusions:1、 We choose a series of monoterpenes. Calculate the structures energy of monoterpenes andcarbocations. At the same time, we analysis some important monoterpenes: Limonene，α-Phellandrene，α-Terpinene，α-Pinene，β-Pinene，γ-Terpinene，3-Carene. Calculate thestructures in the reaction of these monoterpenes with sulfuric acid, including reactants,intermediates and products. Calculation results show that: the most stable structure isα-Terpinene, which the lowest is β-Pinene. The result is quite agreed with theexperiments.2、 The acidity of solution affect the spcies of products and yield. So is reaction time.Withthe rises of solution acidity, the spcies of products are more.The speed of reaction is faster.