Adsorption and Reactions on TiO₂: Comparison of N,N-Dimethylformamide and Dimethylamine

Abstract

Fourier transform infrared spectroscopy has been employed to study the adsorption and reactions of N,N-dimethylformamide (DMF) and dimethylamine (DMA) on powdered TiO 2 . DMF can be adsorbed in molecular form with the carbonyl interacting with the surface Lewis site (Ti 4+ ) or in dissociative form of OCN(CH 3 ) 2 . Theoretical adsorption study of rutile (110) points out that the C* and O atoms of OC*N(CH 3 ) 2 are bonded at a two-foldcoordinated O site and a five-fold-coordinated Ti site, respectively. The thermal products of DMF/TiO 2 are found to be CO and DMA. Photochemical reaction of DMF on TiO 2 in O 2 generates CO 2 , HCOO, and NCO. O 2 participates in the reaction with its oxygen atoms incorporated into the three products. DMA can be adsorbed in molecular form and imine species on TiO 2 . Photoirradiation of DMA/TiO 2 in O 2 generates CO 2 , HCOO, NCO, and imine species. Interestingly, DMF and OCN(CH 3 ) 2 are produced after postirradiation thermal treatment of DMA on TiO 2 , possibly from the reaction between residual DMA and HCOO photoproduct.

Towards the Development of Advanced Packing Design for Distillation in Rotating Packed Beds

“…To analyze the mass transfer performance of the specific RPB, the number of theoretical stages ( N th ) and the resulting HETP value are used as a measure of overall and packing‐specific separation efficiency. This allows for better comparability of performance data with respect to the dimensions of the investigated RPB and packing, compared to the regularly derived overall volumetric mass transfer rates ( k G a or k L a ), which are most often calculated based on the integral performance data for the whole RPB, related to the volume of the installed packing , , . It furthermore is of added value for the subsequent analysis regarding the mass transfer contributions of the packing and the casing.…”

“…The article by Cortes‐Garcia et al provides a concise overview and analysis of the available designs with respect to distillation. Experimental investigations have been expanded from conventional single‐block packings for RPBs, like wire mesh , , knit mesh and metal foams , to more complex packing and rotor configurations, as in split packing for enhanced vapor angular slip velocity and several other alternatives .…”

Near Ambient Pressure X-ray Photoelectron Spectroscopy Study of the Atomic Layer Deposition of TiO2 on RuO2(110)

“…The more likely scenario is that around a monolayer of TiO 2 is present after three ALD cycles (which is not enough to completely attenuate an interfacial layer), and the methyl methylenimine more easily desorbs from TiO 2 compared to RuO 2 , resulting in the lower intensity of the component at 397.2 eV. An IR study found that dimethylamine adsorbed to TiO 2 forms methyl methylenimine only upon heating to 200°C , 50 supporting the possibility that, as more TiO 2 covers the surface, less methyl methylenimine is formed. Figure 5 The Journal of Physical Chemistry C Article summarizes the relative amount of nitrogen species through the half-cycles, obtained from peak fits shown in the Supporting Information.…”

Three-dimensional ultrathin In2O3 nanosheets with morphology-enhanced activity for amine sensing

“…This material has a BET surface area of 107 m 2 /g, which is much higher than other reports for In 2 O 3 (normally between 25 to 40 m 2 /g), 21,24,25 also higher than our previous report about In 2 In order to evaluate the gas sensing performance, the sensor device was fabricated as shown in scheme 2 by using the In 2 O 3 nanosheets as sensing materials, and tri-npropylamine (denoted as TPA) was selected as the probe molecule. Metal oxide surface could have some unsaturated metal cations to serve as Lewis site to coordinate with the amine groups, 36,37 as shown in the inset of Figure 6A. 500 to 1500 s, finally the signal became stable after 1500 s ( Figure 6A).…”