石油产品皂化值的测定 应用资料

石油产品皂化值的测定 应用资料将一定量的试样溶解在适宜的溶剂中，如丁酮(甲基乙基酮)、二甲苯、溶剂油或它们的混合溶剂中，并与定量的氢氧化钾乙醇溶液一起加热。过量的碱用酸标准溶液进行滴定，最后计算出皂化值。APAT-0256en京都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD. APAT-0256en Application Note Saponification number of petroleum products 1.Scope The saponification number represents the number of mg of potassium hydroxide required tosaponify 1 g of sample. In this report， we describe an example of how to measure sample to determine itssaponification number using an automatic potentiometric titrator (based on ASTM D94). Estercompounds contained in the sample were saponified by adding an excess amount of potassiumhydroxide， and the remaining potassium hydroxide was titrated with hydrochloric acid to obtainthe saponification number. 2. Precautions 1) Prior to the first titration， prepare the burette by dispensing and aspirating the titrantbetween it and the reagent bottle several times. Once done， purge approximately 10mL ofthe titrant from the burette and out of the titration nozzle. ) Hazardous substance are used in this titration， so it must be performed in a fume hood.Operators must wear appropriate personal protective equipment. 3. Apparatus Main unit Automatic potentiometric titrator (Preamplifier STD)Electrode Glass electrodeDouble junction reference electrode(Internal solution：3.3 mol/L potassium chloride solution) 4. Reagents Titrant 0.5 mol/L Hydrochloric acid standard solution Additive reagents 0.5 mol/L Alcoholic potassium hydroxide solution， 2-butanone， hexanes 京都电子工业株式会社-可睦电子(上海)商贸有限公司 电话：021-54488867 电邮： kemu-kem@163.com 网址： http：//www.kem-china.com 5. Procedure 1Transfer the sample into an Erlenmeyer flask， and weigh precisely.2234 Add 25±1mL of 2-butanone， and make sure the sample appears homogenous.※ Add 25±0.03 mL of 0.5 mol/L alcoholic potassium hydroxide solution. Connect the condenser to the flask， then heat for 30 minutes after refluxing begins.※2 At the end of the saponification， immediately pour 50mL of the hexanes down thecondenser. This not only rinses the condenser but also cools the reaction mixture. 6) Transfer the reaction mixture to a beaker， rinse the inside of the Erlenmeyer flask twicewith 10 mL of hexanes， and combine the washing solution with the solution. 7) Titrate the solution while hot (without reheating) with 0.5 mol/L hydrochloric acid standardsolution.*3 8) Perform blank test by steps 1)~8) without adding sample. ※1 Beforehand dissolve the sample with 15~25mL xylene and add 2-butanone when sample is difficult todissolve. ※2 Adjust the reflux time depending on the sample. ※3 It is especially important to perform the analysis of reaction mixtures with a high melting point as quicklyas (safely) possible， as they tend to solidify. 6. Calculation Saponification number(mgKOH/g))=(BL1-EP1)xTFxK1xC1/S BL1 Titration amount of blank test(mL) EP1 Titration amount (mL) Concentration conversion coeffic ient (g/mol) =56.1SSample size (g) Factor of titrant =0.9925 Unit conversion coefficient (mol/L) =0.5 7.Example (Listed above are example settings. Availability of settings may vary by instrument model.) 京都电子工业株式会社-可睦电子(上海)商贸有限公司电话：021-54488867 电邮： kemu-kem@163.com 一Measurement results Table 1. Blank test Titration (mL) 1 26.4617 2 26.2286 3 26.3662 Mean 26.3522 SD 0.1172 RSD (%) 0.44 Table 2. Sample measurement result Sample (g) Titration (mL) Saponification number (mgKOH/g) 1 1.0060 18.8511 207.58 2 1.0196 18.7254 208.25 3 1.0021 18.8448 208.57 Mean 208.13 SD 0.51 RSD (%) 0.25 8.Reference ASTMD94-07Standard Test Methods for Saponification Number of Petroleum Products 上海市徐汇区宜山路 都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD