The Hydrogenation Of Phytosterols

Phytosterols mainly comes from the vegetable oil,which has many kinds of physiological functions.But phytosterols encountered a number of problems in the application,such as the large of effective dosage,cause side effects and so on,so that its application has be restricted.But the product of hydrogenated phytosterols- phytostanols which do not exist these problems . Phytostanols not only the physiological functions of phytosterols,but also the smll of effective dosage,without any side effect,which is a safe and efficient food additives.At the present time,phytostanols has been widely used in food and clinical medicine fields. Phytostanols alkanol very few in nature,daily application of phyt- ostanols which obtains mainly through the hydrogenation of phytosterols.At present,the preparation processof phytostanols is very little at home and abroad.In this paper,phytosterols as a raw material,it established analytical method to monitor the process of hydrogenation of phytosterols;Raney-Ni and Pd/C as catalyst,study hydrogenated factors on the hy- drogenation rate of phytosterols and to optimize their process parameters.At the same time,used GC-MS verified the structure of phytostanols.The main methods to analytical phytosterols are TCL,Gas Chromatography and UV-high performance liquid chromatography.But because products of the hydrogenated phytosterols-phytostanols which has special structure,it establish- ment to chemical reagents color-iodometric method and the hydroxyl value to det- termine the rate of hydrogenation of phytosterols.According to single factor and orthogonal experiment,the conditions of iodimetry are:solvent volume,(isopropyl alcohol)35mL/g (phytosterols);sampling weight,1.10g;reaction time,50min;volume of water,100mL.Under these conditions,the measured iodine value of phytosterols is 17.64 gI₂/100g.According to single factor and orthogonal experi- ment,the conditions of hydroxyl value are:sampling weight,2.00g;the volume of pyridine - acetic anhydride,4mL/g(phytosterols);pyridine:acetic anhydride(volume),2.5:1;reaction time,80min.Under these conditions,the measured hydroxyl value of phytosterols is 125.08mgKOH/g.With the iodometric method and hydroxyl value method detecting the hydrogenation product of phytosterols,the re- sult laws consistent with the GC-MS.In this paper,phytosterols as a raw material,isopropyl alcohol as a solvent, Raney-Ni and Pd/C as catalyst,study hydrogenated factors on the hydrogenation rate of phyto-sterols,and to optimize their procees parameters by high pressure.â‘ Raney-Ni as catalyst,througha single pressure factors influencing experiment,process conditions of phytosters preparate for phytostanols:reaction temperature,135℃;hydrogen pressure,2.5MPa;reaction time,5.0h;rotating speed,700r/min;phytosterols concentration,40%.Factors influencing the conversion were system- ati-cally investigated.The optimum reaction conditions found by orthogonal design method were:reaction temperature,135℃;hydrogen pressure,2.5MPa;reaction time,5.0h;rotating speed,700r/min;phytosterols concentrations,40%.Under these conditions,the hydrogenation rate of phytostanols is 94.18% and hydroxyl value is 124.79mgKOH/g;â‘¡Pd/C as catalyst,through a single pressure factors in- fluencing experiment,process conditions of phytosterols preparate for phytostano- ls:reaction temperature,130℃;hydrogen pressure,2.6MPa;reaction time,4.5h;rotating speed,550r/min;catalyst concentrations,1.5%.Factors influencing the conversion were systematically investigated.The optimum reaction conditions fou- nd by orthogonal design method were:reaction temperature,130℃;hydrogen pre- ssure,2.6MPa;reaction time,4.5h;rotating speed,580r/min;catalyst conce- ntrations,1.5%.Under these conditions,the hydrogenation rate of phytostanols is 93.65% and hydroxyl value is 125.04mgKOH/g.The chemical structure of phytostanols is complex.Synthesized phytostanols's structure was cornfirmed by GC-MS.GC-MS conditions:3800-2200 GC-MS,Thermo Fisher;elastic quartz capillary column AB5 MS(30m×O.25nm×0.25um);carrier gas,high-purity nitrogen;column temperature,280℃;injector temperature,290℃;split ratio,pre-20s is 5% and after is 15%;scan frequency,998.74;scan method,FULL SCAN;scan mode,35.0～650.0U;traffic,1ml/min.In addition , it preliminarly discussed hydrogenation mechanism about Raney-Ni and Pd/C catalyst for phytosterols in this paper,which provided research directions to improve and optimize the best catalytic conditions.