MEASUREMENT OF HENRYS LAW CONSTANTS FOR C1 AND C2 CHLORINATED HYDROCARBONS
MEASUREMENT OF HENRYS LAW CONSTANTS FOR C1 AND C2 CHLORINATED HYDROCARBONS
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DOI：
10.1021/es00156a012
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发表时间：
1987-02-01
影响因子：
11.4
通讯作者：
GOSSETT, JM
中科院分区：
文献类型：
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作者：
GOSSETT, JM
提出了一种改进的EPICS程序测量亨利常数，其中原来的假设等溶质质量添加到瓶对已被取消通过重量核算，从而提高精度。在10 - 35 ℃的温度下，对13种挥发性C1和C2氯代烃进行了改进。C，表示无因次亨利常数（Hc）的范围为0.05至1.8。亨利常数的平均变异系数（CV）为3-4%;然而，通过使用瓶对内液体体积的更大差异，CV可降低至估计的2.5- 3.5%。在非常低的亨利常数（即，Hc < 0.1）。在亨利常数的这些测量中使用了挥发性溶质的稀释水溶液混合物（也存在甲醇）。与以前的单溶质测定结果的比较支持使用混合物-至少在这里探讨的范围内。评价了6种化合物的离子强度对表观亨利常数的影响，KCl浓度高达1.0 M。离子强度的实际影响似乎是最小的。在20 ℃时，盐析系数（k）为0.107 - 0.213 L·cm·mol-1。C.
A modification to the EPICS procedure for measuring Henry''s constants is proposed, wherein the original assumption of equal solute mass additions to bottle pairs has been eliminated via a gravimetric accounting, resulting in increased precision. The modified procedure was applied to 13 volatile C1 and C2 chlorinated hydrocarbons at temperatures from 10 to 35.degree. C, representing a range in dimensionless Henry''s constant (Hc) of from 0.05 to 1.8. The mean coefficient of variation (CV) in Henry''s constant was 3-4%; however, by employment of greater differentials in liquid volumes within bottle pairs, CV may be reduced to an estimated 2.5-3.5%. Precision deteriorates markedly at very low Henry''s constants (i.e., Hc < 0.1). Dilute aqueous mixtures of volatile solutes (with methanol also present) were employed in these measurements of Henry''s constant. Comparison with previous results from single-solute assays supports the use of mixtures - at least within the range explored here. The effects of ionic strength on apparent Henry''s constants were evaluated for six of the compounds, with KCl concentrations up to 1.0 M. The practical impact of ionic strength appears to be minimal. Salting-out coefficients (k) ranged from 0.107 to 0.213 L.cntdot.mol-1 at 20.degree. C.