Phthalic Anhydride - ACS Reagent Chemicals (ACS Publications)

Monograph pubs.acs.org/doi/book/10.1021/acsreagents

Phthalic Anhydride (1,3-Isobenzofurandione)

Downloaded by CORNELL UNIV on May 20, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4272

Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents

ABSTRACT This monograph for Phthalic Anhydride provides, in addition to common physical constants, a general description including typical appearance, applications, and change in state (approximate). The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Melting Point, Residue after Ignition, Chloride, Sulfate, Heavy Metals, and Iron.

C6H4(CO)2O

Formula Wt 148.12

CAS No. 85-44-9

GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . white solid Applications . . . . . . . . . . . . . . . . . . . . . . . . buffers Change in state (approximate) . . . . . . . . . . . . melting point, 130 °C

SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.0–100.2% C8H4O3 Melting point . . . . . . . . . . . . . . . . . . . . . . . Not more than 3 °C range, including 131 °C Maximum Allowable Residue after ignition. . . . . . . . . . . . . . . . . . 0.01% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.002% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.003%

© 2017 American Chemical Society

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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.

DOI:10.1021/acsreagents.4272 ACS Reagent Chemicals, Part 4

ACS Reagent Chemicals

Monograph

pubs.acs.org/doi/book/10.1021/acsreagents

Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 5 ppm Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 5 ppm

TESTS Assay


(By acid–base titrimetry). Accurately weigh about 0.3 g into a 150 mL beaker containing 15.0 mL of 0.5 N morpholine methanolic solution (described below) and approximately 80 mL of methanol. Stir at least 30 min, and titrate potentiometrically with 1 N hydrochloric acid volumetric solution. Similarly, titrate a blank containing 15.0 mL of 0.5 N morpholine methanolic solution and 80 mL of methanol. One milliliter of 1 N hydrochloric acid corresponds to 0.1481 g of C6H4(CO)2O.

For the Assay

M o r p h o l i n e M e t h a n o l i c S o l u t i o n , 0 . 5 N . Dilute 4.4 mL (4.4 g) of morpholine to 100 mL with methanol.

Melting Point [Part 2: Measurement of Physical Properties; Melting Point].

Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Gently ignite 10.0 g in a tared, preconditioned crucible or dish. Ignite at 800 ± 25 °C for 15 min. (Reserve this residue for the test for iron.)

Chloride Mix 0.50 g of sample with 0.5 g of sodium carbonate, and add 10–15 mL of water. Evaporate on a hot plate (~100 °C), and ignite until the mass is thoroughly charred, avoiding an excessively high temperature. When the sample is completely ignited, cool, and extract the fusion with 10 mL of water and 2 mL of nitric acid. Filter through chloride-free filter paper, wash with water to a volume of 20 mL, and add 1 mL of silver nitrate reagent solution. Any turbidity should not exceed that produced by 0.01 mg of chloride ion in an equal volume of solution containing 0.5 g of sodium carbonate, 2 mL of nitric acid, and 1 mL of silver nitrate reagent solution.

Sulfate Mix 3.0 g of sample with 1.0 g of sodium carbonate in a platinum crucible, add 20 mL of water, and evaporate to dryness on a hot plate (~100 °C). Ignite completely, taking care to protect the fusion from the flame because of the presence of sulfur compounds in the natural gas. Cool, dissolve the residue in 20 mL of water, add 2 mL of 30% hydrogen peroxide, and boil for 5 min. Add 3 mL of hydrochloric acid and evaporate to dryness on the hot plate. Dissolve the residue in 10 mL of water, filter, and wash with 10 mL of water. To the filtrate, add 1 mL of 1 N hydrochloric acid and 2 mL of 12% barium chloride reagent solution. Any turbidity should not be greater than that of a standard prepared as follows: Evaporate 1 g of sodium carbonate, 2 mL of 30% hydrogen peroxide, and 3 mL of hydrochloric acid to dryness on a hot plate (=100 °C). Dissolve the


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ACS Reagent Chemicals

Monograph

pubs.acs.org/doi/book/10.1021/acsreagents

residue and 0.09 mg of sulfate ion (SO4) in sufficient water to make 20 mL, and add 1 mL of 1 N hydrochloric acid and 2 mL of 12% barium chloride reagent solution. Compare 10 min after adding the barium chloride to the sample and standard solutions.

Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 2]. Use 4.0 g of sample.

Iron


[Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. To the residue from the residue after ignition test, add 3 mL of hydrochloric acid, cover with a watch glass, and digest on a hot plate (~100 °C) for 15–20 min. Remove the cover, and evaporate to dryness. Dissolve the residue in 5 mL of hydrochloric acid, filter if necessary, and dilute with water to 100 mL. Use 20 mL of this solution.


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Phthalic Anhydride - ACS Reagent Chemicals (ACS Publications)

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