1、MONOETHANOLAMINE IN SOLUTIONSBY COLOR INDICATOR TITRATIONUOP Method 825-81SCOPEThis control method is used for the analysis of monoethanolamine (MEA) in solutions used to removeacid gases, such as hydrogen sulfide and carbon dioxide from hydrocarbon streams. The lower limit ofdetection is approximat
2、ely 0.5 wt-%.OUTLINE OF METHODThe amine sample is diluted with water and titrated with a standard sulfuric acid solution to the methylred indicator endpoint.APPARATUSBeaker, 250-mLBuret, 50-mL, with Teflon stopcock, 0.1-mL subdivisionsCylinder, graduated, 100-mL, glass, 1.0-mL subdivisionsHot plate,
3、 adjustable heat, Sargent-Welch Scientific Co., Cat. No. S-41000 A, or equivalentPipet manipulator, Sargent-Welch Scientific Co., Cat. No. S-69793, or equivalentPipet, serological, calibrated for blow-out, one-milliliter capacity, Sargent-Welch Scientific Co., Cat. No.S-69625-C, or equivalentStirrer
4、, magnetic, with Teflon-covered stirring bar, Sargent-Welch Scientific Co., Cat. No. S-76490, orequivalentREAGENTSAll reagents shall conform to the specifications established by the Committee on Analytical Reagents ofthe American Chemical Society, when such specifications are available, unless other
5、wise specified.References to water mean deionized or distilled water.Methyl red indicator solution, 0.1 wt-% concentration. Dissolve 0.1 g of methyl red in 100g of water.IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TODETERMINE THE APPLICABILITY OF REGULATORY LI
6、MITATIONS PRIOR TO USE. EFFECTIVE HEALTH ANDSAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE 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 MATER
7、IALS USED INTHIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTIONEQUIPMENT (PPE). 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 Met
8、hods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service atserviceastm.org, 610.832.9555 FAX, or 610.832.9585 PHONE.2 of 2825-81Sulfuric acid solution, aqueous, 0.05 M, standardizedPROCEDUREBecause of the potential hazards resulting from the liberation of gaseou
9、s H2S during this analysis, arrangethe apparatus in an efficient hood. Pipet one milliliter of the amine solution sample into a beaker containing100 mL of water and a magnetic stirring bar. Remove any remaining sample from the pipet into the waterby blowing into the pipet. With viscous samples, rins
10、e the pipet into the beaker with water. Add 3 drops ofmethyl red indicator solution to the sample solution and turn on the magnetic stirrer. Titrate the samplesolution with standard 0.05 M sulfuric acid to a definite pink endpoint. Place the beaker on the hot plateand heat to boiling for one minute.
11、 If the solution remains pink, use the first endpoint. If the solution turnsyellow, cool the solution and titrate again to a definite pink endpoint. Take the final reading for the totalvolume of titrant used.In the titration of samples containing H2S, if the color of the methyl red indicator is dest
12、royed, moreindicator should be added during the titration. A lean (regenerated), as opposed to rich, amine solutionshould be analyzed whenever possible since the presence of H2S and CO2 tends to make the methyl redendpoint less definite.CALCULATIONSCalculate the concentration of monoethanolamine in
13、the sample solution as follows:12.2 AMonoethanolamine, g/100 mL VM=where:A = standard sulfuric acid solution, mLM = molarity of sulfuric acid solutionV = sample volume, mL12.2 AMonoethanolamine, wt - % SVM=where:S = specific gravity of sample, 60/60 F (15.6/15.6 C)A, M and V are as previously define
14、dPRECISIONAn estimated standard deviation is not reported since insufficient data are available at present to permitthis calculation with at least 4 degrees of freedom. It is estimated that duplicate analyses should agreewithin 0.1 g/100 mL or 0.1 wt-%.TIME FOR ANALYSESThe elapsed time for one analysis is 1.0 hour. The labor requirement is 0.5 hour.REFERENCEMethod SM-1M, The Girdler Corp., Louisville, KYSUGGESTED SUPPLIERSargent-Welch Scientific Co., 7300 N. Linder Ave., Skokie, IL 60076
