Supporting Information

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1 Supporting Information Oxidation of Ethyl Ether on Borate Glass: Chemiluminescence, Mechanism and Development of a Sensitive Gas Sensor Jing Hu, Kailai Xu, Yunzhen Jia, Yi Lv,* Yubao Li, Xiandeng Hou* Key Laboratory of Green Chemistry & Technology at College of Chemistry, Sichuan University, Chengdu, Sichuan , China and Analytical & Testing Center, Sichuan University, Chengdu, Sichuan , China * To whom correspondence should be addressed. lvy@scu.edu.cn; houxd@scu.edu.cn. College of Chemistry. Analytical & Testing Center. S1

2 1. Computational Methods Calculations of reaction processes were carried out using the Gaussian 03 suite of programs. 1 All structures of reactants, transition states, and products were completely optimized with Gaussian s implementation of the B3LYP 2 hybrid density functional method using the G** basis set for all atoms. The stationary points were characterized by frequency calculations in order to verify that minima and transition structures have zero and one imaginary frequencies, respectively. Zero-point energy corrections (unscaled) were also evaluated from the frequency calculations. The intrinsic reaction coordinate (IRC 3 ) calculations were employed to check the energy profiles connecting each transition structure to the two associated minima of the proposed mechanism. Geometry optimizations and frequency calculations for the radicals in the first excited state were performed with Gaussian s CI-Singles method 4 at the same level in their ground state. The transition energies from the first excited state to the ground state were also calculated at the optimized geometry by TDDFT method GC/MS And FT-IR Assay The GC/MS chromatograms were shown in Figure S1. Figure S1 (b) stands for the resultant gases collected at 110ºC, and no products were detected. By comparison among Figure S1 (c), Figure S1 (d) and Figure S1 (e), it can be seen that higher temperature leads to more abundant and complex products. The IR spectra of resultant gases at 160 C and 245 C were shown in Figure S2. It can be seen that no CO 2 was found in product gases at 160 C but at 245 C ( cm -1 and cm -1 ). S2

3 S3

4 Figure S1. GC/MS chromatograms of resultant gases at different reaction temperature of 110ºC (b), 160ºC (c), 210ºC (d), and 245ºC (e). (a) the blank, i.e., HPLC grade acetonitrile; in (a), acetonitrile (5.156 min); and background impurity (1.677 min). In (b), ethyl ether (1.839 min); acetonitrile (5.184 min); and background impurity (1.679 min). In (c), air (2.166 min); acetaldehyde (2.358 min); ethanol (2.536 min); ethyl ether (2.674 min); acetylformaldehyde (2.966 min); acetic acid (3.558 min); 2-methyl-1,3-dioxolane (3.958 min); vinyl methanoate (4.650 min); acetyl anhydride (5.276, min); and background impurity (0.225, 0.365, 2.117, 3.133, 4.259, 4.433,4.820 min). In (d), ethyl ether (1.841 min); acetaldehyde (1.983 min); ethyl methanoate (2.543 min); ethyl acetate (3.100 min); methanol (3.181 min); ethanol (3.750 min); 2-methyl-1,3-dioxolane (4.074 min); acetonitrile (5.164 min); acetyl anhydride ( min); acetic acid ( min); and background impurity (0.115, 0.358, 1.682, min). In (e), ethyl ether (1.852 min); acetaldehyde (1.992, min); ethyl methanoate (2.544 min); ethyl acetate (3.102 min); methanol (3.167 min); ethanol (3.728 min); 2-methyl-1,3-dioxolane (4.040 min); acetonitrile (5.138 min); dimethyl peroxide ( min); acetyl anhydride ( min); ethyl ethoxy(hydroxy) acetate ( min); acetic acid ( min); and background impurity (1.694, 1.733, , , min). S4

5 Figure S2. The IR spectra of resultant gases at (a) 160 C and (b) 245 C. No CO 2 was found in gases at 160 C but at 245 C ( cm -1 and cm -1 ). S5

6 3. GC Assay Figure S3. The concentrations of the products (acetaldehyde and acetic acid) at increased temperatures. At 160 C, acetaldehyde was not detected by GC but it was found in the more sensitive GC/MS assay. The higher the reaction temperature, the higher the product concentrations. 4. Investigation of Reaction Temperature Figure S4. The effect of temperature on the CL signal and the signal-to-noise ratio. Air flow rate, 400 ml min -1 ; ethyl ether concentration, 11.9 µg ml -1 ; and surface material, borate glass. CL signal, and S/N. S6

7 5. Investigation of Carrier Gas Figure S5. The effect of air flow rate on the CL signal and the signal-to-noise ratio. Heating voltage, 125 V; ethyl ether concentration, 11.9 µg ml -1 ; and surface material, borate glass. CL signal, and S/N. 6. Effect of Boric Oxide on CL Signal intensity Figure S6. The effect of boric oxide on the CL signal intensity. Sintered with boric oxide means that a third of the soda-lime glass tube s surface was sintered with boric oxide powder. Temperature, 240ºC; flow rate, 500 ml min -1 ; and ethyl ether concentration, 11.9 µg ml -1. S7

8 7. Selectivity Study Figure S7. Selectivity study, with the signal intensity of ethyl ether as the standard. Temperature, 240ºC; flow rate, 500 ml min -1 ; and the concentrations of ethyl ether or the foreign substance, 27.6 µg ml Glass Composition Table S1. Composition of Pyrex 7740 glass, borate glass (BJTY), borate glass (GG-17) and soda-lime glass. The analytical data were provided by the certified commercial laboratory, Chengdu Rock & Mineral Analytical Center (CRMAC), Chengdu, Sichuan , China. Composition (%) Glass type Note SiO 2 B 2 O 3 Na 2 O K 2 O Al 2 O 3 CaO MgO Fe 2 O 3 ZnO Pyrex < 0.9 Ref. 6 BJTY < < 0.02 Provided GG < 0.02 by Soda-lime < 0.02 CRMAC S8

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