1、 COPYRIGHT 1981 UOP LLCALL RIGHTS RESERVEDUOP Methods are available through ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken PA 19428-2959,United States. The Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service atserviceastm.org,
2、610.832.9555 FAX, or 610.832.9585 PHONE.HYDROGEN FLUORIDE IN HFALKYLATION REGENERATOR BOTTOMSUOP Method 379-81SCOPEThis method is for determining hydrogen fluoride (HF) in HF alkylation regenerator bottoms. Thebottoms material can be either a single or 2-phase system; the upper phase in a 2-phase sy
3、stem is rich inorganic material and contains little HF, while the lower phase is rich in HF. The lower phase may containlarge concentrations of water when there is appreciable water present in any of the feed streams. Thismethod is applicable to both types of samples.OUTLINE OF METHODThe sample is w
4、eighed into a polyethylene bottle, diluted with water, extracted with isooctane, and analiquot of the aqueous phase is titrated with standard sodium hydroxide, using phenolphthalein as theindicator.APPARATUSBalance, analytical, 2000 g capacity, capable of weighing to 0.01 g, Mettler PC 8000, availab
5、le fromSargent-Welch Scientific Co., or equivalentBeaker, polyethylene, 250-mLBottles, polyethylene, with screw caps, 500- and 1000-mLBuret, 50-mL, with Teflon stopcock, 0.1-mL subdivisionsPipet, polyethylene, 10-mLPipet, polypropylene, 100-mL, Bel-Art Products, Cat. No. H37906, or equivalentStirrer
6、 magnetic, with Teflon-covered stirring barIT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TODETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH ANDSAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTIL
7、IZE THISPROCEDURE IN THE MANNER PRESCRIBED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS(MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED INTHIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTIONEQUIPMENT (PPE).2 of 3379-81
8、REAGENTSAll reagents shall conform to the specifications established by the Committee on Analytical Reagents ofthe American Chemical Society, when such specifications exist, unless otherwise specified. References towater mean deionized or distilled water. Unqualified references to solutions mean aqu
9、eous solutions.Isooctane, ASTM gradePhenolphthalein, 1% solution. Dissolve 0.5 g of phenolphthalein in 50 g of ethyl alcohol.Sodium hydroxide, 1 M, standardized with potassium hydrogen phthalate to 4 significant figures. Store ina polyethylene bottle.PROCEDUREBefore this analysis is started, put on
10、rubber gloves, face shield and protective clothing appropriate forworking with HF or HF-containing materials. Work in a well-ventilated hood; otherwise, provide means toavoid inhaling any HF fumes (see PRECAUTIONS).Clean and dry a 500-mL polyethylene bottle and weigh it and a cap to the nearest 0.01
11、 g. Pipet 100 mL ofwater into the bottle and cap it. Weigh the capped polyethylene bottle and contents to the nearest 0.01 g. Ifthe sample is single-phase, add by pipet 10 mL of sample to the bottle. If the sample is 2-phase, shake thesample container first and then immediately pipet 10 mL of sample
12、 into the bottle. Cap the bottle and weighit to the nearest 0.01 g. This increase in the weight of the bottle is the sample weight. Adjust the contents ofthe bottle to a final weight of about 400 g with water; weigh to the nearest 0.01 g. Shake the bottle for oneminute and allow it to stand for 10 m
13、inutes. Add 25 mL of isooctane to the bottle, shake it for one minuteand allow it to stand for 10 minutes. This allows the phases to separate.Weigh to the nearest 0.01 g a clean and dry 250-mL polyethylene beaker containing a Teflon-coveredmagnetic stirring bar. Transfer by pipet, a 100-mL aliquot o
14、f the diluted acid lower phase (be careful not toinclude any of the hydrocarbon phase) into the polyethylene beaker. Reweigh the beaker to the nearest 0.01g. Add 5 drops of the phenolphthalein indicator solution to the aliquot and turn on the magnetic stirrer.Titrate the aliquot with standard 1.0 M
15、sodium hydroxide to a persistent red color. While titrating, washdown the sides of the beaker frequently with water to ensure that the entire solution is titrated.CALCULATIONSObtain the weight-percent of HF as follows:2V AHydrogen fluoride, wt-%BWM=where:A = final weight to which the sample was dilu
16、ted (sample + water), gB = weight of 100-mL aqueous aliquot taken for titration, gM = molarity of sodium hydroxide solution used for titrationV = volume of standard sodium hydroxide solution used for titration, mLW = weight of sample taken for analysis, g3 of 3379-81PRECAUTIONSEven dilute HF solutio
17、ns can cause painful and dangerous burns if not washed off the skin immediately.Wear rubber gloves, face shield and protective clothing at all times. If any of the sample liquids or theuntitrated aqueous solutions come into contact with the skin, wash the area for 10-15 minutes with runningwater, an
18、d seek medical attention immediately.PRECISIONThe estimated standard deviation (esd) based on the indicated replicates is shown below. Duplicate resultsby the same operator should not be considered suspect unless they differ by more than the amounts shownin the “allowable difference” column (95% pro
19、bability).Type ofSampleNumber ofReplicatesLevel,wt-% HFesd,wt-% HFAllowableDifference,wt-% HFRegenerator Bottoms 6 5 0.04 0.15TIME FOR ANALYSISThe elapsed time for one analysis is one hour. The labor requirement is also one hour.SUGGESTED SUPPLIERSBel-Art Products, Pequannock, NJ 07440Sargent-Welch Scientific Co., 7300 N. Linder Ave., Skokie, IL 60076
