Study On The Relationship Of Chromatographic Retention Values-Structure-Calorific Values Of Alcohol Compounds

The combustion of fossil fuel and its huge environmental pollution make it necessary to develop and utilize renewable alternative energy-alcohol compounds.Because of its low calorific value,the experimental determination of alcohol compounds is difficult and restricted by environmental conditions.Therefore,it is of great significance for the study of the relationship of chromatographic retention value-structure-calorific value to select separation conditions and explore chromatographic retention mechanism,to improve the calorific values of alcohol compounds.Some researches,including the application of quantum chemistry and molecular connectivity index in the study of correlation between chromatographic retention value and structure of alcohol compounds,between calorific value and structure,between chromatographic retention value and calorific value,are still lacking until now.In this paper,it was explored by the correlation of calorific value and structure of alcohol compounds to reduce the manpower and material consumption.From the close correlation between chromatographic retention value and structure,this study was to find out whether there was a relationship between chromatographic retention value and calorific value,that is,by means of a simple chromatographic determination,a efficient way was researched to improve the alorific values of alcohol compounds,which would help to develop and utilize the renewable clean energy.The main work and conclusions were as follows.(1)Optimization of the determination conditions of alcohol compounds chromatographic retention values and data analysis of chromatographic retention values.The chromatographic conditions of eleven kinds of alcohol compounds(methanol?alcohol?n-propanol?isopropyl alcohol?n-butyl alcohol?sec-butyl alcohol? tert-butyl alcohol?isoamyl alcohol?n-octanol?n-decanol?n-dodecyl alcohol)were optimized,and the best chromatographic conditions were: pressure of high purity carrier gas(N2?H2?O2)is 0.5 MPa;injection port temperature is 280 ?;the detector temperature is 300 ?;column temperature is programmed at the beginning of using 50 ? and keep 2 min,rise to 250 ? by 10 ?/min then keep 3 min;hydrogen flame ionization detector is used.The chromatographic retention values of eleven kinds of alcohol compounds in the single and mixed samples were determined with two different stationary phases(PH-5 and RTX-WAX).The results showed that there was a little difference between the chromatographic retention values under the same chromatographic conditions.(2)Development and assessment of alcohol compounds chromatographic retention values-structure models.The chromatographic retention values-structure(QSRR)models on the two kinds of stationary phases are established,namely RT1=?5.972 ? 0.047 ET? 1.857 (?)(PH-5 column)and RT2= ? 2.409 ? 0.034 ET(RTX-WAX column),and by using leave-one-out method and interaction test multiple correlation coefficients(R),the results are obtained: R1CV=0.999 and R2CV=0.999,respectively.The models showed that the chromatographic separation of alcohol compounds were associated with the main factors reflecting the molecular branch number (?) index and the characterization of molecular structure parameter ET energy information,which indicated that the chromatographic separation of alcohol compounds were greatly influenced by molecular branch number and energy structure.The chromatographic retention values of alcohol compounds were mainly depended on intermolecular forces,i.e.dispersion force,orientation force and hydrogen bond.But on the RTX-WAX chromatographic column,the chromatographic retention values effect of alcohol comounds were significantly correlated to the variable total energy ET and there only was a linear relationship,which showed that the chromatographic retention values of alcohol compounds were mainly determined by the orientation force and hydrogen bond on the RTX-WAX chromatographic column.The established QSRR equation had a good stability and the better prediction for a series of chromatographic retention values of compounds,and the relationship between the chromatographic retention values and the total energy were significant.(3)Establishment and inspection of alcohol compounds structure-calorific value model.Before the research of related calorific values of alcohol compounds,firstly,the structures were optimized;secondly,by selecting the DMol3 program of Materials Studio 8.0 in software and using base group of DNP,functional GGA/RPBE,center electronic processing mode as full electronic,the theoretical researches on geometric structures and properties of alcohol compounds(vibration frequencies,reactivity,thermodynamics and stability)were carried out and the part quantum parameters of alcohol compounds were calculated.QSPR model has been established between calorific value and structural descriptors of alcohol compounds,namely,Y= 358.625 +1521.500 EHOMO?0.031 ET.The model showed that the calorific values of alcohol compounds were significantly correlated to the total energy ET,highest occupied orbital energy EHOMO.When the quantum chemical parameters and molecular connectivity indexes were used to establish multiple linear regression model,the model was unstable,which illustrated that the changes of calorific values of alcohol compounds influenced by molecular structure and molecular electronic behavior were different.The model can predict the calorific value properties soundly.(4)Determination of calorific values.According to the different proportion of 5:1~5:5 for two hybrid alcohol compounds,the results(n=3)showed that the calorific values reduced gradually with the increase of the percentage of methanol;while the percentage of methanol was the same,the calorific values of mixed alcohol compounds had a general increase with the increase of numbers of carbon atoms added.In hybrid system,there is the minimum calorific value contribution for ethanol and the maximum for positive lauryl alcohol,respectively.(5)Correlation analysis of chromatographic retention values and calorific value of alcohol compounds.The correlation of the alcohol compounds chromatographic retention values and the calorific value was analyzed.It was found that both chromatographic retention values of alcohol compounds and their calorific values had a significant correlation with total energy in the system on the two different stationary phases.Under the same calorific value,the greater the polarity of chromatographic column are,the greater are the chromatographic retention values.Under the different calorific value,the chromatographic retention values of two kinds of chromatographic columns tend to rise gradually with the increase of caloric values.The chromategraphic retention values of alcohol compounds have a positive correlation with the calorific values.