Time filter

Source Type

Chen L.,Max Planck Institute for Polymer Research | Chen L.,Nanchang University | Baumgarten M.,Max Planck Institute for Polymer Research | Guo X.,Max Planck Institute for Polymer Research | And 5 more authors.
Journal of Materials Chemistry C | Year: 2014

Solution-processable hexathiaheptacene dithienothieno[2,3-d;2′, 3′-d′]benzo[1,2-b:4,5-b′]dithiophenes (DTTBDT a-d) with various alkyl groups were synthesized by triflic acid induced ring closure. UV/Vis absorption, photoluminescence spectroscopy and cyclic voltammetry combined with density functional theory quantum-chemical calculations were performed to determine the photophysical and the electrochemical properties of DTTBDT a-d. In addition, the new hexathiaheptacenes show liquid crystalline properties dependent on their alkyl chain length. As observed from differential scanning calorimetry and polarized optical microscopy compared with DTTBDT a and b, DTTBDT c and d exhibit thermotropic liquid crystalline textures due to the rigid conjugated skeleton and the flexible long alkyl chains. For all four derivatives, the structural analysis indicates the formation of lamellar structures in which, surprisingly, the molecules are poorly packed. This molecular disorder is the main reason for the low performance of the p-type field-effect transistors. This journal is © the Partner Organisations 2014.

Yan T.,Xian Jiaotong University | Xu J.,Xian Jiaotong University | Wang L.,Petrochemical Research Institute | Liu Y.,Petrochemical Research Institute | And 2 more authors.
RSC Advances | Year: 2015

Due to the decrease in light crude oil and the ever-increasing demand for the upgrading of heavy oils, the development of new heavy oil processing technologies has been attracting wide attention. Using supercritical fluids (SCFs) as the reaction medium has great advantages for upgrading heavy oils. The upgrading processes which employ supercritical water (SCW) without catalysts and the effects of different operating conditions are summarized in this work. The temperature and the density of SCW are of great significance to upgrading processes. The upgrading process through partial oxidation and the water gas shift reaction is further discussed. The processes employing other SCFs with different kinds of catalysts are also summarised. Additionally, the role of the SCFs during the upgrading is discussed. According to the development of the upgrading of heavy oils with SCFs, some strategies are proposed to improve the quality of the products and to reduce the coke yield. © The Royal Society of Chemistry 2015.

Ying Y.,Beijing University of Chemical Technology | Zeng F.,Beijing University of Chemical Technology | Wu P.,Petrochemical Research Institute | Yang Q.,Beijing University of Chemical Technology | And 5 more authors.
Huagong Xuebao/CIESC Journal | Year: 2014

The nanoporous structures of metal-organic frameworks (MOFs) can be functionally regulated according to specific targets of interest, and thus such types of solids can be considered as promising industrial catalytic materials. Since interface microenvironments and catalytic properties of MOFs might be affected by the solvents, it is necessary to study the influence of solvent effects on their catalytic activities. Although MOFs with coordinatively unsaturated metal sites (CUMs) have shown promising applications in liquid-phase catalysis, the related solvent effects on the Lewis acid catalytic performance of these CUMs are seldom investigated. In this work, density functional theory calculations were conducted to investigate the solvent effects on the properties of the Lewis acid sites in two typical MOFs, Cu-BTC and MOP-15, where the COSMO (conductor-like solvent model) was used to mimic the dielectric response of the solvent environments. Different relative dielectric constants were considered, including in vacuum, toluene, ethyl acetate, 1, 2-dichloroethane and acetonitrile. Using CO as the probe molecule, the solvent effects were examined by exploring the geometry parameters, the Mulliken charges, and the vibrational frequency as well as the adsorption energy of CO molecule around those CUMs. The strengths of Lewis acid sites could be enhanced with the increase of the dielectric constant. Further, the solvent effects became more evident in CUMs when the organic linkers had higher electronegativity. These observations provide fundamental insights into the regulation of the liquid-phase catalytic activity of MOFs using specific solvents. © All Rights Reserved.

Wang Y.-B.,Petrochemical Research Institute | Hu Y.-Z.,Petrochina | Li W.-L.,Petrochemical Research Institute | Zhang W.-S.,Petrochina | And 2 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2014

In the present paper, based on the fast evaluation technique of near infrared, a method to predict the yield of atmospheric and vacuum line was developed, combined with H/CAMS software. Firstly, the near-infrared(NIR) spectroscopy method for rapidly determining the true boiling point of crude oil was developed. With commercially available crude oil spectroscopy database and experiments test from Guangxi Petrochemical Company, calibration model was established and a topological method was used as the calibration. The model can be employed to predict the true boiling point of crude oil. Secondly, the true boiling point based on NIR rapid assay was converted to the side-cut product yield of atmospheric/vacuum distillation unit by H/CAMS software. The predicted yield and the actual yield of distillation product for naphtha, diesel, wax and residual oil were compared in a 7-month period. The result showed that the NIR rapid crude assay can predict the side-cut product yield accurately. The near infrared analytic method for predicting yield has the advantages of fast analysis, reliable results, and being easy to online operate, and it can provide elementary data for refinery planning optimization and crude oil blending.

Liu P.,Petrochemical Research Institute | Zhang Z.,Petrochemical Research Institute | Zhang Z.,Lanzhou University of Technology | Wang Y.,Petrochemical Research Institute | And 5 more authors.
Zhongguo Xitu Xuebao/Journal of the Chinese Rare Earth Society | Year: 2010

REY (RE=rare earth) zeolites with varying RE content were prepared by ion-exchange procedure in aqueous system. The X-ray diffraction analysis revealed that all RE ions were located at lattice sites, and no feature peaks of RE2O3 were detected in X-ray diffraction patterns. The NH3-temperature programmed desorption technique and infrared spectra of pyridine adsorbed on acid sites were employed to investigate acid properties of REY zeolites. It was found that the REY zeolites with high RE content possessed less Lewis acid sites (151 μmol · g-1) and more strong acid sites in comparison with those of low RE content Y zeolites. The reactive performances of model catalysts incorporating zeolites further demonstrated that the variation of acid properties played a critical role in acid based catalysis and the yield of bottom oil decreased from 5.93% to 5.15% with increasing RE content. Additionally, the infrared spectra of pyridine ring reformation model v19b revealed that RE ions could effectively inhibit the extraction of Al atoms from framework.

Discover hidden collaborations