The standard "ISO 1389-4 Phthalic anhydride for industrial use - Test methods - Part 4: Measurement of colour after treatment with sulfuric acid" developed by the International Organization for Standardization (ISO) describes a method for measuring the colour of phthalic anhydride for industrial use in Hazen units after treatment with sulfuric acid. This standard should be considered together with the standard "ISO 1389-4 Phthalic anhydride for industrial use - Test methods - Part I: General".
The described test method is based in principle on measuring the colour of a test piece after treatment with sulfuric acid by the method specified in the standard “ISO 2211 Liquid chemical products - Colour measurement in Hazen units (platinum-cobalt scale)”.
Distilled water or water of equivalent purity is used during the tests. Also used reagents are:
or
The test is carried out using two colorimetric tubes with a flat bottom, a graduation mark at least 100 mm above the bottom, and matched specifically for the colour of the glass and the height of the graduation mark from the bottom. For the measurement of low colourations, the height of the graduation mark from the bottom should be greater than for the measurement of deeper colours and should be sufficient to allow a clear distinction between the standard Hazen matching solutions when viewed from this deeper liquid. In addition, a 100 ml capacity conical flask made of borosilicate glass and fitted with a ground glass stopper is used in these tests.
Place 5,0 g of test sample in a conical flask and add 50 ml of sulfuric acid solution. The flask is loosely capped and immersed in a boiling water bath for 3 hours, shaking occasionally. The flask is removed from the bath, allowed to cool, and the liquid is transferred to one of the colorimetric tubes. The color is measured by the method specified in the ISO 2211 standard.
Phthalic anhydride is widely used worldwide for an extremely wide range of applications, ranging from the plastics industry to the synthesis of resins, agricultural fungicides and amines. Its production is currently based on the vapor phase oxidation of o-xylene and naphthalene.
The primary use of phthalic anhydride is as a precursor to phthalate esters, which are used as plasticizers in vinyl chloride. Phthalic anhydride is derived from phthalic anhydride by the alcoholysis reaction.
Phthalic anhydride is widely used in industry for the production of certain dyes. A well-known application of this reactivity is the preparation of the anthraquinone dye quinizarine by reaction with para-chlorophenol and subsequent hydrolysis of the chloride. Phenolphthalein can be synthesized by condensation of phthalic anhydride with two equivalents of phenol under acidic conditions.
The primary use of phthalic anhydride is as a chemical intermediate in the manufacture of plastics from vinyl chloride. Phthalate esters, which act as plasticizers, are derived from phthalic anhydride. Phthalic anhydride is used in the production of polyester resins and alkyd resins used in paints and varnishes, insect repellents, and urethane polyester polyols. Phthalic anhydride has also been used as a rubber flame retardant and retardant.
Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the standard “ISO 1389-4 Phthalic anhydride for industrial use - Test methods - Part 4: Measurement of color after treatment with sulfuric acid” with its trained and expert staff and advanced technological equipment.
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