石油产品中硫醇硫含量的测定 应用资料

石油产品中硫醇硫含量的测定 应用资料将烃类试样称重后溶解在含有少量氨水的异丙醇溶剂中，用硝酸银的异丙醇标准溶液进行电位滴定，采用玻璃电极为参比电极、银-硫化银电极为指示电极。硫醇硫的含量以μg/g为单位给出。KM京都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD.APAT-0142en APAT-0142en Application Note Mercaptan sulfur of petroleum products IndustryPetroleumInstrumentAutomatic potentiometric titratorMeasurement method ：Potentiometric titration / Precipitation titrationStandardsUOP Method 163， SN/T 4951 1. Scope Mercaptan sulfur in test samples were measured based on “UOP Method 163HydrogenSulfide and Mercaptan Sulfur in Liquid Hydrocarbons by Potentiometric Titration”. Test sampleswere prepared to almost 100 ppm and 1 ppm by dissolving octanethiol in toluene. A test sample and concentrated ammonia solution were dissolved in 2-propanol， and then thesolution was potentiometrically titrated with silver nitrate 2-propanol solution. An inflection pointon the titration curve was regarded as the endpoint. The quantity of mercaptan sulfur wascalculated from the volume of silver nitrate 2-propanol solution used to titrate sample to endpoint. 2. Precautions 1) Handle the reagents in a well ventilated room or a draft chamber. 2) Rinse electrodes with suitable solvent and then pure water after each measurement. 3) Immerse the silver/silver-sulfide electrode into 100 mL of titration solvent containing 0.5mL of 0.1 mol/L silver nitrate solution for 5 minutes， after washing electrodes. 4) Prepare silver sulfide coating on the surface of silver electrode again by the method describedin“6. Procedure，-Preparation of silver/silver-sulfide electrode-“， when the coating becomesrough or the titration curves become noisy. 5) 0.1 mol/L silver nitrate 2-propanol solution is standardized at an interval not shorter than theconcentration changes by more than 0.0005mol/L. 3. Post-measurement procedure 1) Clean the glass electrode with alcohol and keep lower half of the electrode immersed inwater. 2) Clean the silver electrode with alcohol and wipe. Then， keep in a dry condition. 4. Apparatus Main unit Automatic potentiometric titrator (preamplifier ： STD)Electrode Silver electrode (with silver sulfide coating)pH glass electrode 5. Reagents ·0.1 mol/L silver nitrate solution ·0.01 mol/L silver nitrate 2-propanol solution Prepare this solution daily by diluting 0.1 mol/L silver nitrate solution with 2-propanol. ·0.001 mol/L silver nitrate 2-propanol solution Prepare this solution daily by diluting 0.01 mol/L silver nitrate solution with 2-propanol. ·Concentrated ammonia solution (28%) ·1% sodium sulfide (Na2S) solution Dissolve 1 g of anhydrous NazS or 3 g of NazS·9HO in water and dilute to 100 mL with water. 京都电子工业株式会社-可睦电子(上海)商贸有限公司 上海市徐汇区宜山路333号1201室电话：021-54488867 电邮： kemu-kem@163.com 网址： http：//www.kem-china.com 6. Procedure -Preparation of silver/silver-sulfide electrode- 1) Burnish detection part of electrode with polishing paper included with the product. 2) Wash the electrode with pure water and wipe dry. 2) Immerse the electrode in mixture of 96 mL of 2-propanol， 1 mL of concentrated ammoniasolution and 8 mL of 1% NazS solution， and heat the mixture to 60°℃*. 3) Keep the temperature of the solvent at 60℃ * and add 10 mL of 0.01 mol/L silver nitrate2-propanol solution for 10 minutes with stirring. 4) Wash the electrode with water and wipe off surplus silver sulfide. *Though heating operation is not described in the standard， good silver sulfide coating isformed by this operation. -Measurement of 100 ppm sample- 1) Add 100 mL of 2-propanol into a 200mL tall beaker. 2) Add approximately 1 mL of concentrated ammonia solution. 3) Add approximately 50 g of sample and measure mass of it to the nearest 0.1 mg. 4) Titrate with 0.01 mol/L silver nitrate 2-propanol solution. -Measurement of 1 ppm sample- 1) Add 150 mL of 2-propanol into a 300mL tall beaker. 2) Add approximately 1 mL of concentrated ammonia solution. 3) Add approximately 100 g of sample and measure mass of it to the nearest 0.1 mg. 4) Titrate with 0.001 mol/L silver nitrate 2-propanol solution. 7.Calculation Mercaptan sulfur (mass-ppm)=EP1×TF×C1×K1/S EP1 Titer (mL) Factor of titrant=0.9990Ci Concentration conversion coefficient= 0.32 mg/mL (100 ppm sample)0.032 mg/mL (1 ppm sample) K1 Unit conversion coefficient =1000 S Mass of sample (g) 上海市徐汇区宜山路333号1201室电话：021-54488867 电邮： kemu-kem@163.com 网址： http：//www.kem-china.com -Results-100 ppm Sample Results Mass of Mercaptan sample Titer sulfur (g) (mL) (mass-ppm) 1 49.1585 14.4340 94 2 49.5134 14.6195 94 3 49.1704 14.5369 95 Mean 94 SD 一 一 0.6 RSD (%) 一 一 0.6 1 ppm Sample Results Mass of Mercaptan sample Titer sulfur (g) (mL) (mass-ppm) 1 98.7940 3.1435 1.0 2 98.4737 3.1301 1.0 3 98.4903 3.1613 1.0 Mean 一 一 1.0 SD 一 一 0.0 RSD(%) 一 一 0.0 9. Summary Two test samples were measured three times respectively， and the results of them showed agood repeatability. In some samples， verification of the measurement capability is required. In such case， pleasecontact us. 1) UOP Method 163-10 Hydrogen Sulfide and Mercaptan Sulfur in Liquid Hydrocarbons byPotentiometric Titration 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