APHA color

The general sales specification under which maleic anhydride is sold ia the United States specifies a white fused mass or briquettes of 99.5% minimum assay and 52.5°C minimum crystallisation poiat. The melt color specification is 20 APHA maximum with a maximum APHA color of 40 after two hours of heating at 140°C. Four grams of maleic anhydride ia 10 milliliters of water are to be completely soluble. The resulting solution is to be colodess. The acidity resulting from maleic acid is allowed to be a maximum of 0.2%. 

Analytical and Test Methods. Measurement of the sohdification point using a highly sensitive thermometer and of APHA color by comparison of molten samples to APHA standards is straightforward. Specific impurities are measured by gas chromatography. A nonaqueous titration is used to determine phthahc acid content. 

Terephthahc acid is pure white, and molten dimethyl terephthalate is colorless. Impurities or degradation products can be yellow or brown, so the darkness of either a solution of terephthahc acid in dimethylform amide or molten dimethyl terephthalate can be compared to APHA color standards. 

APHA color (269) is usually one of the specifications of PTMEG, sometimes viscosity is another (270). Melt viscosity at 40°C is often used as a rough measure of the molecular weight distribution within a narrow molecular weight range. Sometimes an empirical molecular weight ratio,... 

Apparent equivalent weight deterrnined by titration with hydrochloric acid. APHA color determined by ASTM D1209, platinum—cobalt method. 

APHA color is deterrnined using ASTM D1209 percent water is deterrnined by Kad Eischer titration following ASTM E203. Detailed analytical procedures are available in the fiterature (1) or from producers. 

Color can be removed effectively and economically with either alum or ferric sulfate at pH values of 5—6 and 3—4, respectively. The reaction is stoichiometric and is a specific reaction of the coagulant with the color to form an insoluble compound (17). The dosage required may be as high as 100—150 mg/L (380—570 mg/gal). Raw-water colors may be as high as 450—500 units on the APHA color scale. The secondary MCL (maximum contaminant level) for color in the finished water is 15 units, although most municipal treatment plants produce water that seldom exceeds 5 units. 

In the manufacture of ethylene dibromide, gaseous ethylene is brought into contact with bromine by various methods, allowing for dissipation of the heat of reaction (100—102). Eree acids are neutralized and the product maybe fractionally distilled for purification. Typical specifications call for a clear Hquid with 99.5% purity min sp gr (25/25°C), 2.170—2.180 boiling range, 130.4—132.4°C APHA color, 200 max water, 200 ppm max acidity as HCl, 0.0004 wt % max and nonvolatile matter, 0.0050 wt % max. 

The light chlorophenols, normally have a purity greater than 98.5%, but they often reach over 99%, or even 99.5% with direct phenol chlorination. The APHA color test is always below 100. For 2,4,6-ttichlorophenol, the 2,4,5-trichlorophenol content constitutes an essential quaUty index and should be under 20 mg/kg. None of the light chlorophenols contain any polychlorodibenzoparadioxins or polychlorodibenzofurans. 

Readily Carbonizable Substances Determine as directed under Readily Carbonizable Substances, Appendix IIB. A mixture of 25 mL of 95% sulfuric acid (cooled to 10°) and 25 mL of sample has no more color than 3.5 mL of platinum-cobalt CS, diluted to 50 mL with water (equivalent to not more than 35 APHA color units). 

ASTM D4890, Standard Test Methods for Polyurethane Raw Materials Determination of Gardner and APHA Color of Polyols, 2003. 

APHA color deteimined by ASTM D1209, platinum—cobalt method. 

Chem. Descrip. Butyl stearate CAS 123-95-5 EINECS/ELINCS 204-666-5 Uses Raw material for spin finishes, surfactants oiling agent for textiles processing aid for rubber lubricant, plasticizer for plastics additive in paints, inks base for cosmetics solvent for pharmaceuticals Propertbs APHA color 25 max. solid sol. in n-hexane, xylene, ethanol m.p. 21-24 C vise. 7.7 cp (30 C) acid no. 1 max. iodine no. 2 max. sapon. no. 167-178 Exceparl EH-P [Kao Corp.]... 

APHA color scale n. Abbreviation for American Public Health Asscoation color scale developed for visually evaluating slight yellowness of solutions. It is based on dilutions of a platinum-cobalt standard solution of 500 APHA. This single-number color scale was originally developed by Hazen, and may also be referred to as the Hazen color scale. 

Hazen color scale n. See apha color scale. 

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