Vacuum Urged Distillation Purification Studies Of 1,8 - Cineole

Eucalyptus oil resources are abundant and the yield enlarges continuously in China. A great account of Eucalyptus oil contained 80% 1,8- cineole are used to export, but the pure cineole can't be produced in a large-scale and the highly value products hardly come into international market. A great number of compounds that have similar molecular structure and molecular weight and have similar physical and chemical properties that made it difficulty to purify cineole. In this paper, under the background of Eucalyptus trees planted increasingly in YunNan, highly purified eucalyptus oil was exacted from crude eucalyptus oil by vacuum batch urging distillation which can promote traditional industry and the yield in the field of the natural products and form high and new extraction technique.The paper mainly contains the following points:1.Distillation range was measured, which can account for content and phase balance properties of complicated Eucalyptus oil products and can be used to choose the utilities and production methods. The composition of 1,8-cineole was measured and analyzed by GC showed that crude Eucalyptus oil contains 53.4% 1,8-cineole and its distillation range is from 116.5℃to 188.7℃.2.The saturated vapor pressures of 1,8-cineole and limonene were measured and their related Antoine parameters (a, b, c) were regressed as follows: 1,8-cineole (14.0308, 2340.1468, 138.5771), limonene (16.0649, 3681.2772, 211.2291). Then, the average molar heat of vaporization for Antoine equation was combined with Clapeyron equation: 1,8-cineole 43.01kJ·mol^-1, limonene 42.71 kJ·mol^-1. The base data are very important for extracting cineole and designing industry process.3.The viscosity and density of crude Eucalyptus oil were measured under 25℃as follow: 2.1001×10^-3Pa·s and 0.9019 g/cm³.θ-squeezing rings are used in Packed Column, the minimum spray density l_min and total holdup were estimated as follows: 0.01474 m³·m^-3·s^-1 and 0.07377 m³/m³, which can provide important references in designing batch distillation.4.The urging solvent research was discussed in vacuum batch urging distillation experiment. It was showed that urging solvent would increase the contents of 1,8-cineole in Eucalyptus oil, improved the total column temperature distribution and reduced the operation cycle.5.Through the design parameters of batch distillation, the vacuum batch urging fractionation method was discussed in the experiment. The results showed that the maximum content of 1,8-cineole product reached 93.4% under the following operational condition: kettle temperature is from 93℃to 95℃and t Column top temperature is from 69℃to 70℃and the Column top reflux ratio is 9 and the Column top pressure is 1.76kPa.