63394-00-3Relevant articles and documents
Biggin, S.,Gay, M.,Enderby, J. E.
, (1984)
Generation of nanopores during desorption of NH3 from Mg(NH 3)6Cl2
Hummelshoj, Jens S.,Sorensen, Rasmus Zink,Kustova, Marina Yu.,Johannessen, Tue,Norskov, Jens K.,Christensen, Claus Hviid
, p. 16 - 17 (2006)
It is shown that nanopores are formed during desorption of NH3 from Mg(NH3)6Cl2, which has been proposed as a hydrogen storage material. The system of nanopores facilitates the transport of desorbed ammonia away from the interior of large volumes of compacted storage material. DFT calculations show that there exists a continuous path from the initial Mg(NH3)6Cl2 material to MgCl2 that does not involve large-scale material transport. Accordingly, ammonia desorption from this system is facile. Copyright
Solid state synthesis of nano-sized AlH3 and its dehydriding behaviour
Duan,Hu,Xue
, p. 3466 - 3474 (2015)
Aluminum hydride (AlH3) has a high gravimetric hydrogen capacity (10.1 wt%) and has attracted considerable attention due to its potential application for hydrogen storage. Up to now, almost all the routes developed for the synthesis of AlH3 are energy-consuming and economically impractical for mass production. In this study, a cost effective route of solid state reactive milling was proposed to synthesize AlH3 using aluminum chloride and cheap metal hydrides as starting reagents, with the LiH/AlCl3, MgH2/AlCl3, and CaH2/AlCl3 reaction systems being experimentally investigated. The reaction progress and products during reactive milling were characterized by XRD and 27Al NMR, and the morphology as well as the microstructure of the as-milled samples by SEM and TEM, respectively. It was found that nano-sized γ-AlH3 could be synthesized by reactive milling with commercial AlCl3 and nanocrystalline MgH2 as reagents. Based on the XRD and NMR analyses as well as the TEM observation, the average size of the γ-AlH3 phase in the as-synthesized γ-AlH3/MgCl2 nanocomposite was estimated to be about 8.5 nm. By an isothermal dehydrogenation test, the as-synthesized γ-AlH3 was found to have a quite high hydrogen desorption capacity and fast kinetics, with a hydrogen desorption amount of about 9.71 wt% within 9080 s at 220 °C.
Ring-opening polymerization of cycloolefins with MgCl2
Buchacher,Fischer,Aichholzer,Stelzer
, p. 163 - 171 (1997)
Until now polymerization catalysis was linked to transition metal chemistry with only few exceptions. However, in our work we will show that the main group metal salt MgCl2 can give rise to oligomerization and polymerization of olefins. Since t
MgCl2.6PhCH2OH - A new molecular adduct as support material for Ziegler-Natta catalyst: Synthesis, characterization and catalytic activity
Gnanakumar, Edwin S.,Thushara,Bhange, Deu S.,Mathew, Renny,Ajithkumar,Rajamohanan,Bhaduri, Sumit,Gopinath, Chinnakonda S.
, p. 10936 - 10944 (2011)
Benzyl alcohol has been used to prepare a single phase MgCl 2.6BzOH molecular adduct as a support for an ethylene polymerization catalyst (Ziegler catalyst). The structural, spectroscopic and morphological aspects of the MgCl2.6BzOH molecular adduct and the Ziegler catalyst have been thoroughly studied by various physicochemical characterization techniques. The presence of MgO6 octahedrons due to the interaction of Mg2+ with six -OH groups of the benzyl alcohol is confirmed from a Raman feature at 703 cm-1, and structural studies. The supported catalyst activity has been evaluated for the ethylene polymerization reaction. The lower polymerization activity of the titanated Ziegler-Natta catalyst compared with a standard catalyst is attributed to the strong interaction of titanium chloride with the support and associated electronic factors.
Synthese von Dicarbollyl-Komplexen der Elemente Phosphor und Arsen: Roentgenstrukturanalyse von ClAs
Jutzi, P.,Wegener, D.,Hursthouse, M.
, p. 277 - 289 (1991)
The lithium salt Li2 reacts with the element(III) chlorides PCl3 and AsCl3 to yield the heterodicarbollyl compounds 1 and 2, respectively, of the type ClEl (1, El=P;2, El=As).Reaction of 1 and 2 with iPrMgCl leads to the corresponding isopropyl-derivatives iPrEl (3, El=P; 4, El=As). 3 can also be obtained in low yields from the reaction of Li2 with iPrPCl2. 1 and 2 react with AlCl3 to give the adducts ClEl*AlCl3 (5, El=P; 6, El=As).Treatment of 1 with AgBF4 gives, under elimination of AgCl and BF3, the fluorinated analogon FP (7).Comparison of the bonding situation in 1-7 with that in known isoelectronic cage-compounds of group 14 elements suggests a distorted icosahedral structure for 1-7, which has been proved in the case of 2 by an X-ray diffraction study.
Polyethers as potential electron donors for Ziegler-Natta ethylene polymerization catalysts
Pirinen, Sami,Pakkanen, Tuula T.
, p. 177 - 183 (2015)
Poly(ethylene glycol) (PEG) and poly(tetrahydrofuran) (PTHF) were studied as possible electron donors for heterogeneous Ziegler-Natta catalysts employed for ethylene polymerization. Two synthetic routes were applied for the preparation of the catalysts by mixing the polyether and TiCl4 with δ-MgCl2 support in the same step or at different stages of the catalyst synthesis. The Fourier transform infrared spectroscopy (FT-IR) studies revealed a clear interaction between PEG and δ-MgCl2 inducing changes in the chain conformation of the polyether. If PEG was added at the same stage with TiCl4, a yellow PEG/TiCl4 complex was formed and the activity of the catalyst was decreased. A partial decomposition of PTHF to tetrahydrofuran (THF) in contact with δ-MgCl2 was evidenced from the FT-IR and nuclear magnetic resonance spectroscopy data. The decomposition could be induced by the Lewis acid sites or by possible organomagnesium compounds present in the synthesized δ-MgCl2. However, the decomposition did not have a negative effect on the polymerization behavior of the prepared catalysts, when compared to the reference catalysts where THF was initially used as a donor. The catalysts prepared with polyethers as electron donor showed good activity in ethylene (around 1000 kgP/molTi h) and in ethylene/1-hexene (around 1600 kgP/molTi h) polymerizations.
Indirect, reversible high-density hydrogen storage in compact metal ammine salts
Sorensen, Rasmus Z.,Hummelshoj, Jens S.,Klerke, Asbjorn,Reves, Jacob Birke,Vegge, Tejs,Norskov, Jens K.,Christensen, Claus H.
, p. 8660 - 8668 (2008)
The indirect hydrogen storage capabilities of Mg(NH3) 6Cl2, Ca(NH3)8Cl2, Mn(NH3)6Cl2, and Ni(NH3) 6Cl2 are investigated. All four metal ammine chlorides can be compacted to solid tablets with densities of at least 95% of the crystal density. This gives very high indirect hydrogen densities both gravimetrically and volumetrically. Upon heating, NH3 is released from the salts, and by employing an appropriate catalyst, H2 can be released corresponding to up to 9.78 wt % H and 0.116 kg H/L for the Ca(NH 3)8Cl2 salt. The NH3 release from all four salts is investigated using temperature-programmed desorption employing different heating rates. The desorption is found mainly to be limited by heat transfer, indicating that the desorption kinetics are extremely fast for all steps. During desorption from solid tablets of Mg(NH3) 6Cl2, Mn(NH3)6Cl2, and Ni(NH3)6Cl2, nanoporous structures develop, which facilitates desorption from the interior of large, compact tablets. Density functional theory calculations reproduce trends in desorption enthalpies for the systems studied, and a mechanism in which individual chains of the ammines are released from the surface of the crystal is proposed to explain the fast absorption/desorption processes.
Oxidation of magnesium with cyclopentadienyl(triphenylphosphine)nickel chloride in aprotic solvents
Maslennikov,Panteleev,Spirina,Maslennikov
, p. 1488 - 1491 (2008)
The products of magnesium oxidation with cyclopentadienyl(triphenylphosphine)nickel chloride were revealed. Effective equilibrium constants of adsorption of the reagents on the metal surface, entropy and enthalpy of these processes, rate constants, and activation energy were determined. A probable scheme of the process is assumed.
Nanoscale structural characterization of Mg(NH3)6Cl2 during NH3 desorption: An in situ small angle X-ray scattering study
Jacobsen, Hjalte Sylvest,Hansen, Heine Anton,Andreasen, Jens Wenzel,Shi, Qing,Andreasen, Anders,Feidenhans'l, Robert,Nielsen, Martin Meedom,St?hl, Kenny,Vegge, Tejs
, p. 255 - 260 (2007)
Complex metal hydrides progressively display improved hydrogen storage capacity, but they are still far from fulfilling the requirements of the transport sector. Recently, indirect storage of hydrogen as ammonia in Mg(NH3)6Cl2 has shown impressive capacity and reversibility. Here, we present an in situ nanoscale structural characterization of the thermal decomposition of Mg(NH3)6Cl2 using small angle X-ray scattering (SAXS). We observe the growth of polydisperse spherical Mg(NH3)2Cl2 crystallites forming a skeletal structure, the subsequent agglomeration of MgCl2 and formation of a nanoscale porosity consisting of 25-30 nm wide channels, which may account for the exceptional fast reloading of the material.
Kirsh, Y.,Yariv, S.,Shoval, S.
, p. 393 - 408 (1987)
Supported Ziegler-Natta catalysts for propylene polymerization. Study of surface species formed at interaction of electron donors and TiCl4 with activated MgCl2
Stukalov, Denis V.,Zakharov, Vladimir A.,Potapov, Alexander G.,Bukatov, Gennady D.
, p. 39 - 49 (2009)
Adsorption of various internal electron donors (IDs) and coadsorption of these IDs with TiCl4 on activated MgCl2 have been studied by DRIFT and analytical techniques. As a result, the structures of the ID species on the (1 0 4) and (
McGillivray, G. W.,Smith, W. E.
, p. 177 - 182 (1987)
Formation of unsaturated C3 hydrocarbons by the protolysis of magnesium sesquicarbide with ammonium halides
Disch, Sabrina,Cheetham, Anthony K.,Ruschewitz, Uwe
, p. 969 - 973 (2008)
The protolysis of magnesium sesquicarbide, Mg2C3, with inorganic acids provides an interesting alternative to the more common hydrolysis of ionic carbides for obtaining their respective hydrocarbons. In particular, protolysis reactio
Ionic liquids as an efficient medium for the mechanochemical synthesis of α-AlH3 nano-composites
Duan,Hu,Ma
, p. 6309 - 6318 (2018/04/23)
Aluminum hydride (AlH3) is one of the most promising hydrogen storage materials that has a high theoretical hydrogen storage capacity (10.08 wt%) and relatively low dehydriding temperature (100-200 °C). In this work, we present a cost-effective route to synthesize the α-AlH3 nano-composite by using cheap metal hydrides and aluminum chloride as starting reagents and to achieve liquid state reactive milling. The LiH/AlCl3 and MgH2/AlCl3 reaction systems were systemically explored. The phase identification of the obtained products was carried out by XRD and the morphology observed by TEM characterization. It was found that the α-AlH3 nano-composite can be successfully synthesized by reactive milling of commercial AlCl3 and LiH in a neutral ionic liquid ([2-Eim] OAc). Based on XRD analysis and TEM observation, an average grain size of 56 nm can be obtained by the proposed mechanochemical process. By setting the isothermal dehydrogenation temperature between 80 and 160 °C, the as-synthesized α-AlH3 nano-composite exhibits an advantage in hydrogen desorption capacity and has fast dehydriding kinetics. The hydrogen desorption content of 9.93 wt% was achieved at 160 °C, which indicates the potential utilization of the prepared nanocomposite in hydrogen storage applications.
