UOP 274-2013 Platinum in Fresh Catalysts by Spectrophotometry.pdf

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1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB

2、ED HEREIN CAN BE HAZARDOUS. SAFETY DATA SHEETS (SDS) OR EXPERIMENTAL SAFETY DATA SHEETS (ESDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 1982, 1989, 1994, 2013 UOP LLC. All rights reserved. Nonco

3、nfidential UOP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.832.9585 P

4、HONE. Platinum in Fresh Catalysts by Spectrophotometry UOP Method 274-13 Scope This method is for determining platinum in fresh gamma-alumina, theta-alumina, or silica/gamma-alumina catalysts at concentrations from approximately 0.05 to 1.0 mass-% by spectrophotometry. Catalysts containing rhenium c

5、annot be analyzed by this method. Any other elements that produce colored ions in the dissolution or color-development steps constitute a positive interference. These include chromium, rhodium, cobalt and molybdenum, but other elements can also interfere. References UOP Method 918, “Collection and G

6、rinding of Adsorbents and Catalysts for Analysis,” www.astm.org UOP Method 954, “Loss on Ignition (LOI) for Fresh, Regenerated, Used, and Spent Catalysts, Catalyst Supports, and Adsorbents,” www.astm.org UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method All three

7、types of fresh catalyst are sampled and ground as described in UOP Method 918, “Collection and Grinding of Adsorbents and Catalysts for Analysis.” gamma-Alumina catalyst can be digested by either hot plate digestion or by microwave digestion. theta-Alumina catalyst is digested by microwave digestion

8、. Silica/gamma-alumina catalyst must be digested by hot plate. Silica is removed from silica-containing catalysts as silicon tetrafluoride by fuming with hydrofluoric and sulfuric acid in a Teflon beaker on a hot plate, according to a specified procedure. After the sample has been digested by the ap

9、plicable technique and the platinum dissolved, a hydrochloric acid solution of stannous chloride is added to the platinum solution to produce a yellow color and spectrophotometric measurements are made at 403 nm. The concentration of the platinum is determined by comparing the absorbance of the samp

10、le solution to a standard calibration curve prepared from matrix-matched, platinum-stannous standard solutions. The platinum concentration is corrected to a volatile-free basis from an LOI at 700 or 900C by UOP Method 954, “Loss on Ignition (LOI) for Fresh, Regenerated, Used, and Spent Catalysts, Ca

11、talyst Supports, and Adsorbents,” depending on catalyst composition. 2 of 16 274-13 Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Balance, readable to 0.0001 g Balance, top-loading, readable to 0.01 g, 2000-g capa

12、city Beakers, Berzelius, tall-form with spout, 200-mL capacity, graduated 25- to 150-mL, borosilicate glass, VWR Scientific, Cat. No. 13922-040, minimum 4 required Beakers, Griffin, borosilicate glass, graduated, 20-, 400-, and 1000-mL, Fisher Scientific, Cat. Nos. 02-540E, L, and P, respectively Be

13、aker, Teflon, 250-mL, Fisher Scientific, Cat. No. 02-593-5B Bottle, glass, amber, narrow mouth, round, 237-mL, with molded plastic, conical polyethylene-lined cap, Fisher Scientific, Cat. No. 02-911-900 Bottle, washing, polyethylene, Right-to-Know Safety Wash Bottles, Distilled Water, 500-mL, Fisher

14、 Scientific, Cat. No. 03-409-11E Brush, scrubbing Bucket, Nalgene high density polyethylene, 9.5-L capacity, Fisher Scientific, Cat. No. 03-687-30 Buret, weighing, Ace Glass, Cat. No. 9176-02 Calculator or personal computer, with software capable of least squares analysis Cell, spectrophotometric, 1

15、0-mm path length, near-UV glass, rectangular, universally matched, Fisher Scientific, Cat. No. 14-385-910A. Alternatively, a stationary flow cell may be used (see Note 6). Crucibles, low wide-form porcelain, 30-mL, with cover, Fisher Scientific, Cat. Nos. 07-955E and 07-970G, respectively, several r

16、equired. Each crucible must be inscribed with an identification number using a hard-tipped scriber. Alternatively, Coors Ceramic marking ink may be used. Cylinder, graduated, polypropylene, 25-mL, Fisher Scientific, Cat. No. 08-572B Cylinders, graduated, borosilicate glass, 10-, 25-, 50-, and 500-mL

17、, Fisher Scientific, Cat. Nos. 08-549-5B, C, D, and H, respectively Filter forceps, stainless steel, Fisher Scientific, Cat. No. 09-753-50 Filtration apparatus, vacuum, borosilicate glass filter holder, 47-mm diameter funnel, 300-mL base with coarse frit support for filter, anodized aluminum spring

18、clamp, Neoprene stopper; vacuum filtering flask, 1-L, Millipore, Cat. Nos. XX10 047-00 and -05, respectively Flasks, volumetric, Class A, 100-, 200-, 250-, 1000-, and 2000 mL, Fisher Scientific, Cat. Nos. 10-210-5C, D, E, G, and H, respectively Funnel, filter, 58 angle bowl, short stem, 55-mm diamet

19、er, Fisher Scientific, Cat. No. 10-322C Furnace, programmable, electric, chamber 360-mm wide 300-mm deep 330-mm high (minimum), lined with molded refractory ceramic, capable of maintaining 1000 10C, Fisher Scientific, Cat. No. 10-505-14 Gloves, heavy duty, Fisher Scientific, Cat. No. 11-394-11C Glov

20、es, nitrile, Fisher Scientific, Cat. No. 19-130-1597, size A to FH 3 of 16 274-13 Hot plate stirrer, remote control, adjustable heat and stirrer, ceramic top, heating range to 540C, Fisher Scientific, Cat. No. 11-675-912Q Hot plate (non-stirring), Lindberg H-3, Model No. 53015, metal alloy plate sur

21、face, heating range 80 to 400C, VWR Scientific, Cat. No. 33924-402 (optional) Microwave oven, Ethos EZ, Milestone, Cat. No. 46100, with the following options: Pressure control, non-contact, QPA0203 Quartz rotor, MRQ01053, includes rotor body, cooling tube, quartz vessels, capping station, stoppers,

22、and rack Rotor, segmented, SK-10T, includes 10 rotor segments and 10 complete vessels Rotor, high temperature, HT10400, includes 10 rotor segments, 10 complete vessels, 10 ceramic shields, and temperature sensor Sensing device, infrared, non-contact, IRT0500 Stirring option, ASM45001 Temperature con

23、trol for all vessels, TS0000 Temperature probe for rotors, 50214 Pipets, Mohr, 1-, 5-, 10-, and 25-mL, Fisher Scientific, Cat. Nos. 13-665G, K, M, and N, respectively Pump, vacuum Scoop, weighing, 20-g capacity, nickel alloy, Fisher Scientific, Cat. No. 01-914-38 Scriber, tungsten carbide pencil, Fi

24、sher Scientific, Cat. No. 13-378 Spatula, Fisher scoopula, stainless steel, Fisher Scientific, Cat. No. 14-357 Spectrophotometer, minimum absorbance repeatability of 0.0003 at 0.1 Abs, noise less than 0.00005 Abs (rms) at 0.0 Abs, and 0.0006 Abs (rms) at 2.0 Abs, minimum stability of 0.0003 Abs per

25、hour, readability to 0.0001 Abs, Shimadzu, UV-1800 (see Note 7) Standards, absorbance, spectrophotometric, certified, glass filters, 10 to 30% transmittance, 440 to 635 nm wavelength range, National Institute of Standards and Technology (NIST), Cat. No. SRM-2031a Stirring bars, magnetic, enclosed in

26、 Teflon fluorocarbon, 9.5-mm diameter 25-mm length, Fisher Scientific, Cat. No. 14-512-128 Thermometer, surface, with temperature probe, Omega Engineering, Cat. Nos. HH81A and 88108K, respectively Tongs, beaker, Fisher Scientific, Cat. No. 02-622 Watch glass, borosilicate glass, ribbed, 100-mm diame

27、ter, Fisher Scientific, Cat. No. 02-613B Watch glass, PTFE, Fisher Scientific, Cat. No. 02-617-1G Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. References to water mean deionized or distilled water, e

28、xcept where noted. Alumina, catalyst support 4 of 16 274-13 Catalyst support solution, 40,000 mass/vol-ppm. Prepare in a one-liter beaker by dissolving 40 g of the alumina catalyst support in a solution of 300 mL of water, 250 mL of phosphoric acid and 250 mL of sulfuric acid. After the support has

29、been dissolved by gentle warming, allow the solution to cool to ambient temperature, vacuum filter through a 10.0-m filter into a 1000-mL flask. Transfer the filtrate into a 1000-mL volumetric flask and dilute to the mark with water. The solution is stable indefinitely. Ceramic marking ink, Coors, F

30、isher Scientific, Cat. No. 11-734 (optional) Cleaning compound, detergent, Alconox, VWR, Cat. No. 21835-032 Filter, Whatman, glass microfiber, 47-mm diameter, 934-AH, Fisher Scientific, Cat. No. 09-924-451 Filter, Whatman type WCN, 47-mm diameter, 5.0-m pore size, 7195-004, Fisher Scientific, Cat. N

31、o. 09-905-96 Filters, Teflon membrane, unlaminated, 10.0-m, 47-mm diameter, Millipore, Cat. No. LCWP 047 00 Glass beads, 3-mm, solid, borosilicate, Kimble No. 13500-3, Fisher Scientific, Cat. No. 10-310-1. Rinse with water to remove glass chips and allow to dry before use. Alternatively, a small bor

32、osilicate glass covered magnetic stirring bar may be used. Hydrochloric acid, 37%, trace metal grade, Fisher Scientific, Cat. No. A508SK212 Hydrochloric acid solution, 6N, Fisher Scientific, Cat. No. SA56-1, or, prepare by adding 500 mL of concentrated hydrochloric acid measured with a graduated cyl

33、inder to an equal volume of water in a 1000-mL volumetric flask and mix. Hydrofluoric acid, 48-51%, trace metal grade, Fisher Scientific, Cat. No. A513-500 Hydrogen peroxide, 30%, Fisher Scientific, Cat. No. H325-500 Ice, water Lens paper, optical, Fisher Scientific, Cat. No. 11-996 Microwave mixed

34、acid solution. In a 2-L volumetric flask, combine 720 mL of water with 480 mL of concentrated phosphoric acid and swirl to mix. Add 400 mL of concentrated hydrochloric acid, 20 mL of concentrated nitric acid, and swirl to mix. Allow to cool to room temperature and mix well. Do not dilute to volume.

35、Mixed acid solution. Prepare in a glass beaker by slowly adding 70 mL of concentrated sulfuric acid to 70 mL of water and allow the mixture to return to room temperature. Add 280 mL of concentrated hydrochloric acid and then pour 70 mL of concentrated phosphoric acid into the acid mixture. The mixed

36、 acid solution is stable indefinitely when kept in a stoppered volumetric flask. Nitric acid, 70%, trace metal grade, Fisher Scientific, Cat. No. A509-212 Phosphoric acid, 85%, Fisher Scientific, Cat. No. AC42404-0025 Pipet, dropping, straight tube, with bulb, Fisher Scientific, Cat. No. 13-701 Plat

37、inum standard solution, 1000 mg/L, in 10% hydrochloric acid, SPEX CertiPrep, Cat. No. PLPT3-2X Stannous chloride, dihydrate, Baker Analyzed Reagent Grade, lot analysis provided, 99.9% minimum purity, Avantor Performance Materials, Cat. No. 3980 (see Note 8) 5 of 16 274-13 Stannous chloride solution.

38、 In a glass beaker, dissolve while stirring 50 0.01 g of the stannous chloride in 50 mL of concentrated hydrochloric acid with gentle warming, if necessary. Transfer the solution to a 100-mL volumetric flask and dilute with water to approximately 95 mL. Allow to cool to ambient temperature, dilute t

39、o the mark with water, stopper and mix by inverting several times. Filter the solution through a Whatman glass microfiber filter into a 1-L vacuum filtration flask, using the vacuum filtration apparatus and transfer the solution into another 100-mL volumetric flask. This solution must be prepared da

40、ily. Sulfuric acid, 95-98%, trace metal grade, Fisher Scientific, Cat. No. A510-212 Test paper, potassium iodide-starch, Fisher Scientific, Cat. No. 14-860 Water, deionized or distilled Wipers, Kimwipes EX-L, laboratory wipers, lint free, Fisher Scientific, Cat. No. 06-666A Procedure The analyst is

41、expected to be familiar with general laboratory practices, the technique of spectrophotometry, and the equipment being used. Dispose of used reagents, materials, and samples in an environmentally safe manner according to local regulations. Platinum Standard Solution Convert the concentration of the

42、platinum standard solution from mg/L as listed on the certificate of analysis to mg/g as used for calibration, using Equation 1: P = N1000M (1) where: M = concentration of platinum in standard solution, from certificate of analysis, mg/L N = density of platinum standard solution, from certificate of

43、 analysis, g/mL P = concentration of platinum in standard solution, mg/g 1000 = convert L to mL Sample Grinding 1. Clean the pulverizer and grind the whole pill catalyst samples as described in UOP Method 918, “Collection and Grinding of Adsorbents and Catalysts for Analysis.” 2. Mix the collected,

44、ground sample thoroughly by randomly shaking it for 5 minutes in an appropriate container. Once the mixing is complete, the homogenous powder must not be agitated again until after the sample is taken. Preparation of Platinum Working Standards 1. Calculate the volume of catalyst support solution tha

45、t is required for the matrix match using the Equation 2: X = V TW2500 (2) where: T = approximate alumina content of the catalyst to be analyzed, mass fraction V = final volume of the sample solution for analysis from Table 1, mL W = mass of catalyst sample to be analyzed from Table 1, g X = volume o

46、f catalyst support solution required for the matrix match, mL 6 of 16 274-13 2500 = 000,40 )100()10(6(2a) where: 106 = converts g to g, g/g 100 = final volume of standard solution, mL 40,000 = alumina content in catalyst support solution, g/mL 2. Add the volume of catalyst support solution calculate

47、d in Step 1 to each of four 200-mL borosilicate beakers using a graduated cylinder. 3. From a weighing buret, transfer aliquots corresponding to 0.7, 1.2 and 1.8 g of the platinum standard solution to three of the 200-mL beakers containing catalyst support solution. Weigh each aliquot to the nearest

48、 0.0001 g. Do not add any platinum solution to the fourth beaker, which will be used to prepare a matrix matched blank. 4. Add a Teflon stirring bar or glass boiling beads to each of the four beakers. 5. Cover each beaker with a ribbed borosilicate watch glass and proceed with Step 1 of Preparation

49、of Soluble Platinum Species. Table 1 Masses of Samples and Volume of Stannous Chloride Color Developing Solution at Various Pt Contents Pt Content of Catalyst, mass-% Catalyst Mass Taken for Analysis, g Volume of Stannous Chloride Solution for Color Developing, mL Final Solution Volume for Analysis, mL 0.2 0.8 8 100 0.4 0.4 8 100 0.8 0.4 16 200 1.0 0.4 20 250 Dissolution of gamma-Alumina Catalysts, Using the Hot Plate 1. Weigh, to the nearest 0.0001 g, the appropriate amount of ground catalyst, see Table 1, into a 200-mL borosilicate glass beaker. Take care to