EXPLANATION
The determination of the carbonyl content of polymerization-grade 1,3-butadiene is necessary, since in some polymerization reactions, the presence of carbonyls in excess over some specified amount can have a deleterious effect upon the polymer properties or the reaction itself, or both.
This test method covers the determination of carbonyls (ketones and aldehydes) in C4 hydrocarbons. The applicable range of this test method is 0 - 50 mg/kg carbonyls calculated as acetaldehyde. Other C4 hydrocarbons and their mixtures besides polymerization grade 1,3-butadiene could be tested using this method. However, precision of such analysis is not known.
TEST SUMMARY
A measured amount of sample is added to an alcoholic hydroxylamine hydrochloride solution that has been adjusted to a given coloration using either alcoholic acid or base. The carbonyls will react with the hydroxylamine hydrochloride releasing an equivalent amount of hydrochloric acid which is then back-titrated to the original coloration. A blank containing only methanol and sample is titrated and the sample's results are calculated using the blank adjustment. Results are reported as mg/kg carbonyls as acetaldehyde.
TEST PRECISION
Where X is the average of two test results.
No statement of bias is being made since no accepted reference materials for this test are available.