You-Ying Di,^a,* Yu-Xia Kong,^a Wei-Wei Yang,^a Da-Qi Wang^a and Zhi-Cheng Tan^b

^a College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province, P. R. China
^b Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
* Corresponding author: E-mail: yydi@lcu.edu.cn, diyouying@126.com,
Tel: +86-635-8538299, Fax: +86-635-8239121

Abstract
Crystal structure of N, N-dimethylnorephedrine hydrochloride (C₁₁H₁₈NOCl) (s) has been determined by an X-ray crystallography. The compound is orthorhombic P2₁2₁2₁. Unit cell parameters are a = 7.2486(19) Å, b = 9.674(3) Å, c = 16.952(5) Å; α= 90°, β= 90°, γ= 90°, and Z = 4. Low-temperature heat capacities of the compound were measured by a precision automated adiabatic calorimeter over the temperature range from 80 to 390 K. A polynomial equation of heat capacities as a function of the temperature in the region of 80–390 K was fitted by least square method. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated with 5 K step. In addition, DSC technique was used to determine the melting process of the compound.

Keywords: N, N-dimethylnorephedrine hydrochloride; X-ray crystallography; adiabatic calorimetry; low-temperature heat capacity; thermodynamic function