Origin of High Selectivity of Dimethyl Ether Carbonylation in the 8-Membered Ring Channel of Mordenite Zeolite

2019 ◽  
Vol 123 (25) ◽  
pp. 15503-15512 ◽  
Author(s):  
Yueying Chu ◽  
An-Ya Lo ◽  
Chao Wang ◽  
Feng Deng
Keyword(s):  
Dimethyl Ether ◽  
High Selectivity ◽  
Membered Ring ◽  
Ring Channel

Specific zone within 8-membered ring channel as catalytic center for carbonylation of dimethyl ether and methanol over FER zeolite

2018 ◽  
Vol 557 ◽  
pp. 119-124 ◽  
Author(s):  
Pei Feng ◽  
Guanqun Zhang ◽  
Xiaofang Chen ◽  
Kailu Zang ◽  
Xiujie Li ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Membered Ring ◽  
Catalytic Center ◽  
Ring Channel

Aluminum Siting in the ZSM-22 and Theta-1 Zeolites Revisited: A QM/MM Study

2008 ◽  
Vol 73 (6-7) ◽  
pp. 909-920 ◽  
Author(s):  
Stepan Sklenak ◽  
Jiří Dědeček ◽  
Chengbin Li ◽  
Fei Gao ◽  
Bavornpon Jansang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Chemical Shift ◽  
Nearest Neighbor ◽  
Membered Ring ◽  
Mas Nmr ◽  
Isotropic Chemical Shift ◽  
Reaction Space ◽  
Ring Channel ◽  
T1 And T2 ◽  
Nmr Signals

The Al siting in the silicon rich ZSM-22 and Theta-1 zeolites of the TON structure was investigated analyzing already published 27Al 3Q MAS NMR experimental data using QM/MM calculations. The results of our computations show that Al atoms can be located in 6 framework T positions because the two eightfold sites (T1 and T2) split into four fourfold T sites after an Al/Si substitution. The observed resonance at 55.5 ppm corresponds to the T4 site which is predominantly occupied by Al. This site is not located on the surface of the TON ten-membered ring channel and thus the protonic sites related with the majority of Al atoms in the TON structure exhibit a significantly limited reaction space. The 27Al NMR signals centered at 57.6 and 58.7 ppm correspond to either the T2 and T3 sites, respectively, or only to T2. The T2 and T3 sites accommodate some 40% and up to 10%, respectively, of Al while the T1 site is unoccupied by Al. Isotropic shifts of 61.1 and 61.6 ppm were calculated for Al atoms located in the T1-1 and T1-2 sites, respectively. The effect of a silanol "nest" as a next-next-nearest neighbor on the 27Al isotropic chemical shift of Al located in the T4 site is calculated to be less than 1 ppm.

Synchrotron powder diffraction characterization of the zeolite-based (p-N,N-dimethylnitroaniline–mordenite) guest–host phase

2008 ◽  
Vol 64 (6) ◽  
pp. 713-724 ◽  
Author(s):  
Florence Porcher ◽  
Elena Borissenko ◽  
Mohamed Souhassou ◽  
Masaki Takata ◽  
Kenichi Kato ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Dipole Moments ◽  
Membered Ring ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Crystallographic Study ◽  
Synchrotron Powder Diffraction ◽  
Ring Channel ◽  
New Phase

The crystal structure of a new phase consisting of the inclusion of the hyperpolarizable molecule p-N,N-dimethylnitroaniline (dimethyl-para-nitroaniline or dmpNA) in the large-pore zeolite mordenite (MOR) has been determined from high-resolution synchrotron powder diffraction at 300 and 90 K. The unit-cell parameters and space group at 300 K are similar to those of as-synthesized mordenite. The crystallographic study indicates that the MOR straight channels are almost fully loaded with molecules that are disordered over eight symmetry-related sites. As expected, the molecules are located in the large 12-membered ring channel, at the intersection with the secondary eight-membered channel with which they might form hydrogen bonds. The elongation axes (and then the dipole moments) of the molecules are slightly tilted (28.57°) from [001]. The configuration found suggests an interaction of dmpNA with framework O atoms through its methyl groups.

scholarly journals Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study

2017 ◽  
Vol 7 (5) ◽  
pp. 1141-1152 ◽  
Author(s):  
D. B. Rasmussen ◽  
J. M. Christensen ◽  
B. Temel ◽  
F. Studt ◽  
P. G. Moses ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dimethyl Ether ◽  
Density Functional ◽  
Methyl Acetate ◽  
Flow Reactor ◽  
Reaction Path ◽  
Fixed Bed ◽  
Density Functional Theory Calculations ◽  
Membered Ring ◽  
Functional Theory

Dimethyl ether carbonylation to methyl acetate over mordenite was studied theoretically with density functional theory calculations and experimentally in a fixed bed flow reactor. A new reaction path to methyl acetate entirely in the 8 membered ring was discovered.

Mu-28: an open-framework fluorogallophosphate with a three-dimensional 12-membered ring channel system

2004 ◽  
Vol 177 (10) ◽  
pp. 3721-3728 ◽  
Author(s):  
Ludovic Josien ◽  
Angélique Simon-Masseron ◽  
Volker Gramlich ◽  
Florence Porcher ◽  
Joël Patarin
Keyword(s):  
Three Dimensional ◽  
Membered Ring ◽  
Channel System ◽  
Open Framework ◽  
Ring Channel

Cyclic Alkyl(aryl)boranes for 1,1-Carboboration of Monoalkynyltin Compounds

2013 ◽  
Vol 68 (5-6) ◽  
pp. 493-502 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Peter Thoma ◽  
Wolfgang Milius
Keyword(s):  
Solid State ◽  
High Selectivity ◽  
Ring Expansion ◽  
Membered Ring ◽  
Reaction Products ◽  
State Structure ◽  
Alkyl Aryl ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Techniques

Two cyclic alkyl(aryl)boranes, a 1-bora-indane derivative 1, and a tricyclic derivative 4, containing the boron atom in a six-membered ring, were structurally characterized by NMR techniques in solution. The solid-state structure of the 1-bora-indane 1 was determined by X-ray crystallography. The reactivity of these cyclic alkyl(aryl)boranes towards monoalkynyltin compounds, Me3Sn-C≡C-Me and Me3Sn-C C-Fc (Fc=ferrocenyl), was studied using multinuclear magnetic resonance methods (1H, 11B, 13C, 119Sn NMR). Novel alkenylboranes were formed by 1,1-carboboration reactions. This process involves an expansion of both five- and six-membered rings. Insertion into the respective B-C(aryl) bond was preferred with high selectivity. In the case of the six-membered ring in 4, the ring expansion to seven-membered rings proved to be readily reversible, and the thermodynamically stable reaction products were formed by ring contraction and concomitant transfer of the exocyclic B-nPr group

Reactivity of Seven-Membered-Ring trans-Alkenes with Electrophiles

Synlett ◽  
2017 ◽  
Vol 28 (18) ◽  
pp. 2478-2482 ◽  
Author(s):  
K. Woerpel ◽  
Jillian Sanzone
Keyword(s):  
Driving Force ◽  
High Selectivity ◽  
Membered Ring ◽  
Additional Strain ◽  
Oxygen Gas ◽  
Oxygen Bond ◽  
Silicon Oxygen

Seven-membered-ring trans-alkenes containing a silicon–oxygen bond reacted rapidly with oxygen gas and electron-deficient alkenes and alkynes to give products with high selectivity. Addition of an electron-donating substituent or incorporating additional strain increased the reactivity by over two orders of magnitude. These results indicate that release of strain is not the only driving force for reactivity.

Determination of Dimethyl Ether in Air by Cataluminescence-Based Gas Sensor

2013 ◽  
Vol 739 ◽  
pp. 537-542 ◽  
Author(s):  
Chun Xiu Gu ◽  
Zheng Xing ◽  
Xin Cai ◽  
Jie Zhang ◽  
Bin Juan Gao ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Gas Sensor ◽  
Dimethyl Ether ◽  
High Selectivity ◽  
Optimal Conditions ◽  
Optimized Conditions ◽  
Luminescence Characteristics ◽  
Versus Concentration ◽  
Weak Interference

A rapid and sensitive cataluminescence-based gas sensor utilizing nanosized Y2MnO5as the sensing materials for determining dimethyl ether in air was proposed. The luminescence characteristics and the optimal conditions were investigated in detail. The gas sensor showed high selectivity for dimethyl ether at 620 nm and satisfying activity at 210°C under the optimized conditions. The linear range of cataluminescence intensity versus concentration of dimethyl ether was 5~120 mg/m3, and the detection limit (3σ) was 3 mg/m3. No or weak interference was observed while the foreign substances, such as formaldehyde, ammonia, ethanol, benzene, carbon monoxide and sulfur dioxide, were passing through the sensor under selected conditions. The gas sensor displayed good stability for continuously introducing dimethyl ether over 100 h, and allowed real-time monitoring of dimethyl ether in air.

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