Designati Designation: on: D 1615 1615 – 60 (Reapprov (Reapproved ed 1995)
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AMERICAN SOCIETY FOR TESTING AND MATERIALS 100 Barr Harbor Dr., West Conshohocken, PA 19428 Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
Glycerol, Glycerol, Ethylene Glycol, Glycol, and Pentaerythritol Pentaerythritol in Alkyd Resins1 This standard is issued under the fixed designation D 1615; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e1 NOTE—Keywords were added editorially and editorial changes made throughout in May 1995.
1. Scope Scope
Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagen Reagents ts of the Americ American an Chemi Chemical cal Societ Society y, where where such such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 3.2 Unless otherwise indicated, indicated, references to water water shall be understood to mean reagent water conforming to Specification D 1193.3
1.1 These test methods cover the determination determination of glycerol, glycerol, ethylene glycol, and pentaerythritol in alkyd resins and resin solutions. Other polyhydric alcohols that can be oxidized by period periodic ic acid acid to forma formalde ldehyd hydee or formic formic acid, acid, or both, both, will will interfere with the determination of glycerol and ethylene glycol (see (see Test Method Methodss D 2456 2456 or D 2998 2998). ). Urea, Urea, melami melamine, ne, or phenolic phenolic resins resins interfer interferee and render render this procedure procedure inappliinapplicable. This standa standard rd does not purport purport to addre address ss all of the 1.2 This safe safety ty conc concer erns ns,, if any any, asso associ ciat ated ed with with its its use. use. It is the the responsibility of the user of this standard to establish appro priate safety and health practices and determine the applicability of regulatory limitations prior to use.
NOTE 1—The reagents and samples used in these methods may, under some some conditi conditions ons,, be hazard hazardous. ous. Refer Refer to the manufa manufactu cturer rer’s ’s Materi Material al Safety Safety Data Sheets for specific specific handlin handling g and safety safety precau precaution tions. s. Safe Safe laboratory handling procedures and all applicable OSHA regulations are to be followed. followed.
2. Referenced Documents
GLYCEROL AND ETHYLENE GLYCOL
2.1 ASTM Standards: D 563 Test Test Method Method for Phthal Phthalic ic Anhydr Anhydride ide Conten Contentt of 2 Alkyd Resins and Resin Solutions D 1193 1193 Specification for Reagent Water Water 3 D 1398 1398 Test Test Meth Method od for for Fatt Fatty y Acid Acid Cont Conten entt of Alky Alkyd d Resins and Alkyd Resin Solutions 2 D 2456 Test Method for Identificat Identification ion of Polyhydri Polyhydricc Alcohols in Alkyd Resins 2 D 2998 2998 Test Method Method for Polyhy Polyhydri dricc Alcoho Alcohols ls in Alkyd Alkyd Resins2
4. Summary Summary of Test Test Method 4.1 The primar primary y hydrox hydroxyl yl groups groups of ethyle ethylene ne glycol glycol and glycerol glycerol are oxidized oxidized to formaldeh formaldehyde yde by periodic periodic acid; the secondary hydroxyl group of glycerol is oxidized to formic acid. By acidimetric and iodometric titration, the proportions of formic acid and formaldehyde can be determined respectively, and calculated calculated to glycerol and ethylene ethylene glycol by algebrai algebraicc equations. The equations for the oxidation of the polyhydric alcohols are as follows:
3. Purity Purity of Reagents 3.1 Reagent Reagent grade chemic chemicals als shall shall be used used in all tests. tests. 1
These test methods are under the jurisdiction of ASTM Committee D-1 on Paint and Related Coatings, Coatings, Materials, and Applications Applications and are the direct responsibilit responsibility y of Subcommittee Subcommittee D01.33 D01.33 on Polymers and Resins. Current Current edition approved approved Sept. 19, 1960. Originally issued 1958. Replaces D 1615 – 58 T. 2 Annual Book of ASTM Standards Standards,, Vol 06.03. 3 Annual Book of ASTM Standards Standards,, Vol 11.01.
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American n Reagent Chemicals, American Chemical Society Specifications Specifications,, America Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, Society, see Analar Standards for Laboratory Chemicals, Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, Formulary , U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.
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D 1615 source of heat. Keep the beaker covered with a watch glass 6 during boiling. 7.2.2 Cool to room temperature, and filter through a rapid paper into a 100-mL volumetric flask. (Take the sample for pentaerythritol determination from this same volumetric flask.) Fill to the mark and agitate. 7.2.3 Pipet 20 mL (1 ⁄ 5 aliquot) (Note 2) into a 1-L Erlenmeyer, glass-stoppered flask. Add 2 drops of methyl purple indicator solution and neutralize with NaOH. Pipet into the 1-L flask also 50 mL of HIO 4 solution, stopper, and swirl to mix thoroughly.
C3H8O3 + 2H5I06 glycerol periodic acid ↓
2HCHO formaldehyde
+ HCOOH + 2HIO3 formic iodic acid acid C2H6O2 + H5I06 ethylene periodic glycol acid
+ 5H 2O water
↓
2HCHO formaldehyde
+ HIO3 iodic acid
+ 3H 2O w ater
With pentaerythritol, there is no reaction.
NOTE 2—The aliquot should be so chosen, if possible, that 15 to 20 % of the periodic acid is consumed during the oxidation. Considerable excess of periodic acid is required to complete the oxidation, and in case more than 20 % is consumed the results should be disregarded and a smaller aliquot taken. On the other hand, too small an aliquot is not advisable, for in such a situation the difference between titration and blank is small and any titration errors are magnified.
5. Apparatus 5.1 Burets , 50 and 100-mL capacity. 5.2 Pipets, 20 and 50-mL capacity. 5.3 Beakers, two of 400-mL capacity. 5.4 Erlenmeyer Flasks, four of 1000-mL capacity, glassstoppered. 5.5 Volumetric Flasks, two of 100-mL capacity. 5.6 Graduated Cylinder , 10-mL capacity. 5.7 Filter Paper , fast, qualitative grade. 5.8 Watch Glass.
7.3 Simultaneously prepare two blanks containing 20 mL of water. Allow to stand 50 to 70 min at room temperature. 7.4 To the aliquot of the sample (7.2.3) and the blank, add 100 mL of water and 3 drops of methyl purple indicator and titrate with 0.1 N NaOH solution to neutrality. Use the 50-mL buret and record the volume to the nearest 0.01 mL. 7.5 To the solution that has just been titrated, add 150 mL of water, 30 mL of KI solution, and 25 mL of H 2SO4 (1+5). Titrate with 0.2 N Na2S2O3 solution to faint iodine color, add 10 mL of starch indicator and titrate to the disappearance of the blue color.
6. Reagents 6.1 Methyl Purple Indicator Solution . 5 6.2 Periodic Acid (11 g/L)—Dissolve 11 g of periodic acid (HIO4) in water and dilute to 1 L. Prepare fresh daily and store in a brown bottle. 6.3 Potassium Iodide Solution (200 g/L)—Dissolve 200 g of potassium iodide (KI) in water and dilute to 1 L. 6.4 Sodium Hydroxide, Standard Solution (0.1 N )—Prepare and standardize a 0.1 N aqueous sodium hydroxide (NaOH) solution. 6.5 Sodium Thiosulfate, Standard Solution (0.2 N )— Prepare and standardize a 0.2 N aqueous sodium thiosulfate (Na2S2O3) solution. 6.6 Starch Indicator Solution—Dissolve 5 g of soluble starch in water and dilute to 1 L. Preserve the solution with 1 g of salicyclic acid. 6.7 Sulfuric Acid (1+5)—Carefully mix 1 volume of concentrated sulfuric acid (H 2SO4, sp gr 1.84) with 5 volumes of water.
NOTE 3—If the end point is not stable, as indicated by return of the blue color in the stoppered flask in 5 min, add water and titrate to a stable end point. Use the 100-mL buret and record the volume to the nearest estimated 0.05 mL.
8. Calculations 8.1 Calculate the percentage of glycerol, G, as follows: G 5 @~ A 2 B! N 3 0.09206! / WF # 3 100
where: A
5 millilitres of NaOH solution required for titration of the sample, 5 millilitres of NaOH solution required for titra B tion of the blank, 5 normality of the NaOH solution, N 0.09206 5 grams of glycerol equivalent to 1 mL of 1 N NaOH solution (acidimetric), 5 grams of sample used, and W 5 aliquot fraction 5 1 ⁄ 5. F 8.2 Calculate the percentage of glycerol and ethylene glycol, T , as a percentage of glycerol as follows:
7. Procedure 7.1 Determine the phthalic anhydride in accordance with Test Method D 563. Following this, extract the fatty acids in accordance with 5.6 through 7 of Test Method D 1398, except do not discard the aqueous phase. 7.2 Test the remaining water solution containing the polyalcohols for glycerol and ethylene glycol in the following manner: 7.2.1 Transfer the solution to a 400-mL beaker and evaporate to about 60-mL volume, using an electric hot plate as
~T 5 @~ B 2 A ! N 3 0.023015! / WF # 3 100 8
where: A 8
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5 millilitres of Na 2S2O3 solution required for titration of the sample,
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Methyl purple indicator manufactured by the Fleisher Chemical Co., Benjamin Franklin Station, Washington 4, D.C., U.S. Patent No. 2,416,619, has been found satisfactory for this purpose. 6
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The Speedyvap watch glass has been found satisfactory for this purpose.
D 1615 zaldehyde,7 add 100 mL of technical grade anhydrous methanol (CH3OH). 12.2 Hydrochloric Acid (sp gr 1.19)—Concentrated hydrochloric acid (HCl). 12.3 Methanol-Water Wash Solution (1 + 1)—Mix equal volumes of technical anhydrous CH 3OH and water. (Because of heat of solution, prepare this solution in advance.) One fourth of the wash solution is to be stored in a refrigerator and used cold; the remainder is kept at room temperature.
5 millilitres of Na 2S2O3 solution required for titration of the blank, 0.023015 5 grams of glycerol equivalent to 1 mL of 1 N Na2S2O3 solution (iodometric), 5 normality of the Na 2S2O3 solution, N 5 grams of sample used, and W 5 aliquot fraction 5 1 ⁄ 5. F 8.3 If E is the percentage of ethylene glycol, then 8
B
E 5 1.348~T 2 G !
When E 5 O, the sample is free of ethylene glycol.
13. Procedure 13.1 Transfer an aliquot of the 100-mL of sample solution (7.2.2) containing 0.15 to 0.55 g of pentaerythritol to a 100-mL beaker. Evaporate on a steam bath to a volume of approximately 5 mL. To the hot solution (incipient boiling) add 15 mL of benzaldehyde-methanol reagent and 12 mL of HCl. Swirl and allow to stand at room temperature 15 min, swirling occasionally during this time to prevent the precipitate from adhering to the bottom of the beaker. Place the beaker in an ice bath, maintaining the temperature at 0 to 2°C for 1 h or more. 13.2 Remove the reaction mixture from the ice bath and immediately filter with suction through a weighed fritted-glass crucible of medium porosity. Rinse the beaker with 25 mL of the cold (0 to 2°C) methanol wash solution and add to the crucible. Continue to transfer and wash the precipitate with 100 mL of methanol-water wash solution at 20 to 25°C as follows: 13.2.1 Disconnect the vacuum line, pour a 10-mL portion of the wash solution from the beaker to the crucible, and stir the precipitate to form a homogeneous slurry, using a short flat-end glass rod. Connect the vacuum line and draw the wash solution through the crucible. Repeat this washing operation six times. With the last 30 mL of methanol-water wash solution, rinse the interior walls of the crucible and rinse and remove the short stirring rod. 13.3 Aspirate thoroughly and dry the precipitate at 105°C for 2 h. Cool in a desiccator and weigh.
NOTE 4—In practice, samples containing no ethylene glycol have given calculated E values of up to 1 %. Therefore, samples with E values of 1 % or less should be considered as containing no ethylene glycol, and samples with higher E values may be corrected by 1 % at the discretion of the analyst.
9. Precision and Bias 9.1 Repeatability—The average difference between duplicate runs performed by the same analyst in the same laboratory should approximate the following values: Percentage of glycerol Percentage of glycol
0.1 0.4
Not more than once in twenty times would the difference be expected to exceed: Percentage of glycerol Percentage of glycol
0.3 1.0
9.2 Reproducibility: 9.2.1 The average difference between results obtained by different analysts in different laboratories, when reported as the average of duplicate determinations, should approximate: Percentage of glycerol Percentage of glycol
0.2 0.5
9.2.2 Not more than once in twenty times should the difference be expected to exceed: Percentage of glycerol Percentage of glycol
0.6 1.2
14. Calculations
PENTAERYTHRITOL
14.1 Calculate the percentage of monopentaerythritol, P, of the resin from the precipitate obtained in accordance with 14.3 follows:
10. Summary of Test Method 10.1 Monopentaerythritol reacts with benzaldehyde to form a dibenzal which is crystalline and can be handled gravimetrically.
P 5 @~W 2 1 0.0269! 3 43.6# / W1 F
where: W 1 5 grams of sample, W 2 5 grams of precipitate, and 5 aliquot fraction. F 14.2 To convert the percentage of monopentaerythritol, P, to the percentage of commercial technical monopentaerythritol, use the following arbitrary formula which is based on the assumption that the commercial grade contains 85 % monopentaerythritol:
11. Apparatus 11.1 Beakers, 100-mL capacity. 11.2 Delivery Pipets ( for aliquots), 10 to 50-mL capacity. 11.3 Steam Bath. 11.4 Ice Bath. 11.5 Crucible, medium porosity, fritted glass. 11.6 Suction Flask . 11.7 Water Aspirator . 11.8 Desiccator . 11.9 Drying Oven, capable of maintaining a temperature of 105°C. 11.10 Glass Rod , flat-end.
Commercial monopentaerythritol, % 5 P /0.85
15. Precision and Bias 15.1 Repeatability— The average difference in percentage
12. Reagents and Materials 12.1 Benzaldehyde-Methanol Reagent —To 20 mL of ben-
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Merck, N. F. grade benzaldehyde has been found satisfactory for this purpose.
D 1615 of monopentaerythritol found, between duplicate runs performed by the same analyst in the same laboratory, should approximate 0.25. Not more than once in twenty times would the difference be expected to exceed 0.6. 15.2 Reproducibility —The average difference in percentage of monopentaerythritol found, between results obtained by different analysts in different laboratories, when reported as the
average of duplicate determinations should approximate 0.5. Not more than once in twenty times would the difference be expected to exceed 1.4. 16. Keywords 16.1 alkyd resins; ethylene glycol; glycerol; pentaerythritol
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