Halide content, determination

Ethereal methyl1ithiurn (as the lithium bromide complex) was obtained by the submitters from Aldrich Chemical Company Inc. The checkers used 1.19 M methyl1ithiurn-lithium bromide complex in ether supplied by Alfa Products, Morton/Thiokol, Inc. The concentration of the methyllithium was determined by titration with 1.0 M tert-butyl alcohol in benzene using 1,10-phenanthroline as indicator. The submitters report that ethereal methyllithium of low halide content purchased from Alfa Products, Morton/Thiokol, Inc., gave similar results. 

Process streams from pilot plant experiments are usually retained to evaluate the compatibility of various types of materials of construction. Mass balance information is often sufficient to determine these requirements based on pH, halide content, solvents used, and process temperature. Corrosion testing of pilot plant process streams through the use of electrochemical techniques is often recommended. These results are compiled and documented along with the specifications for the materials of construction. 

Epoxy content is generally determined by wet analytical techniques. ASTM D 1652 is widely used. The most common method is based on the addition of hydrogen halide (e.g., hydrogen chloride, hydrogen bromide, or hydrogen iodide) to the epoxy group. The difference between the amount of acid added and the amount unconsumed, determined by titration with standard base, is a measure of the epoxy content. There are numerous epoxy assay methods based on this technique. The specific method used depends on the resin type being analyzed as well as on the extent to which side reactions can occur. 

Calcium Content Dissolve about 1.5 g of sample, accurately weighed, in 100 mL of water containing 2 mL of 2.7 A hydrochloric acid. While stirring, preferably with a magnetic stirrer, add about 30 mL of 0.05 M disodium EDTA from a 50-mL buret, then add 15 mL of 1 A sodium hydroxide and 300 mg of hydroxy naphthol blue indicator, and continue the titration to a blue endpoint. Each milliliter of 0.05 M disodium EDTA is equivalent to 2.004 mg of calcium (Ca). Halides Determine as directed in the Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB. A 1.2-g sample shows no more turbidity than 0.7 mL of 0.020 A hydrochloric acid. 

Halogens by the Carius Method.— The halogens, chlorine bromim iodinej are also determined by the Carius method. In this case, crystalline silver nitratej nitric acid and the compound under examination are all introduced into the Carius tube. The nitric acid must be kept separate from the compound until after the tube is sealed. After sealing the tube as before, the contents are mixed and the tube heated in the bomb oven. The halogen of the organic compound is converted into silver halide which, when the tube is opened, is carefully washed out, filtered, and weighed. 

The water content in solids and many organic acids, alcohols, esters, ethers, anhydrides, and halides can be determined using Karl-Fischer reagent, composed of iodine, sulfurdioxide, pyridine, and methanol. 

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