A Consistent Determination of the Dimerization Constants of the Self‐Association of 2,2‐Dimethyl‐3‐ethyl‐3‐pentanol in Carbon Tetrachloride from its Infrared Spectral Data

Two equations of linear type (Eqs. 10 and 17 in the text) have been derived to analyze the IR data to determine the dimerization constant consistently. Equation 10 is to be used to fit the integrated absorbances of the monomer band to obtain the molar monomer absorptivity, ?_m, and dimerization constant, K; Eq. 17 is to be used to fit the integrated absorbances of the dimer bands to obtain the molar dimer absorptivity, ?_d, and dimerization constant, K. Thus the same dimerization constant can be independently determined either from the monomer band or from the dimer band. The discrepancy between the two determined values provides an assessment of the consistency of determination. The monomer‐dimer self‐association of 2,2‐dimethyl‐3‐ethyl‐3‐pentanol in the solvent of carbon tetrachloride was chosen to demonstrate the utility of these two equations.     

示波指示技术在动力学分析法中的应用 Ⅰ.利用KBrO_3-KBr-HCI体系测定还原性物质

示波滴定至今主要用于常量或半微量分析。示波滴定终点指示技术能否在微量和痕量分析中发挥作用是一个需要探索的新课题。本文报道用零电流示波双电位指示技术与动力学分析相法相结合的方法测定微量还原性物质。 在反应BrO_3~_ 5Br~- 6H~ =3Br_2 3H_2O中,Br_2的生成速率受动力学控制,在一定条件下d[Br_2]/dt=k。若生成的Br_2达某一特定浓度(终点可用某一方法指示)的时间为t_0,则当该溶液中存在能与Br_2快速反应而与KBrO_3的反应可忽略的还原剂时Br_2达到该浓度的时     

New approach to IR study of monomer-dimer self-association: 2,2-dimethyl-3-ethyl-3-pentanol in tetrachloroethylene as an example

The dimerization of 2,2-dimethyl-3-ethyl-3-pentanol in tetrachloroethylene in the diluted region has been studied at four temperatures by IR spectroscopy. The aforementioned solute compound is chosen because self-association beyond dimerization is hampered by the steric hindrance generated by the bulky sidechains. The integrated absorbances of the monomer bands were treated based on Eq. (9) to obtain its molar absorptivity and dimerization constant. The same dimerization constant as well as the molar absorptivity of dimer band can be obtained based on Eq. (13) from the data treatment of the integrated absorbances of the dimer band. The disparity between two values of dimerization constant determined by two independent sources offers an opportunity to check the consistency of the determination. The standard enthalpy and entropy of dimerization have also been calculated by means of van't Hoff plot, respectively, from the data of temperature-dependent dimerization constants obtained from the monomer bands and dimer bands.     

The synthesis and spontaneous resolution of 2-(2-thioxothiazolidin-3-yl)thiazole

A single crystalline enantiomer of 2-(2-thioxothiazolidin-3-yl)thiazole 5 has been isolated as the major product of the pyrolysis of 3-(2-thiazolin-2-yl)thiazolidine-2-thione 3 (n = 1); the latter isolated as the sole product of the reaction between thiazolidine-2-thione 2 (n = 1) and diethyl azodicarboxylate (DEAD) in benzene.