Solid substitutional

A mixture of polymethylene glycols of the type (CH20) ,xH20 where n is 6- 50. It is a white, amorphous powder having the odour of meth-anal, m.p. I20-130°C. The commercial product contains 95% methanal and is obtained in while flocculent masses when solutions of methanal are evaporated or allowed to stand. When heated it is converted to methanal. Used as a convenient solid substitute for methanal. 

Numerous earlier solid-state [4+4]-photodimerizations of solid (substituted) anthracenes are cited there and mechanistically interpreted on the basis of supermicroscopic AFM data. 

At the present time, one crucial question still remains what is the industrial value of Diphosgene and Triphosgene as liquid and solid substitutes for phosgene Are the two reagents really safer than phosgene ... 

At present, this liquid-solid substitution approach has been extended to the secondary synthesis of zeolites containing Si, Fe, Sn, Ti, Cr, and other heteroatoms. An exception is that BF4 cannot be used for liquid-phase dealumination and boron-addition of zeolites to prepare boron-containing zeolites.[33] In the following galliation of NH4Y will be taken as an example to discuss the isomorphous substitution secondary synthesis technique. 

TABLE 5. Heats of formation of a collection of solid substituted naphthalenes and corresponding benzenes0 ... 

Further to the synthesis of the OMS materials, researchers at Sandia National Laboratories reported the synthesis of a family of microporous niobates, general formula Na2Nb2 xM 06 x(0H)x.H20 (M = Ti, Zr x = 0.04-0.40), prepared from hydrothermal treatment of intimately mixed metal alkoxide precursors. The structure is made up of layers of edge-sharing octahedra interleaved with double ehains of edge-sharing niobate octahedra, in which additional, hydrated sodium eations reside. The niobate chains exhibit solid substitution. These SOMS (Sandia octahedral molecular sieves) demonstrate appreciable ion exchange eapacity and are selective for divalent cations. 

NMR. Severe limitations are however expected in the case of solids having disordered atoms, solid-substitutions or ill-defined hydrogen-atoms positions. To have a chance to correlate structural data to solid-state NMR chemical shifts, one must have a refinement faetor R less than typically 5%. Even if it is very difficult to fulfill these eonditions for most of the silicate minerals, we think that for very well defined structural types and provided that both NMR and X-ray or neutron diffraction measurements have been performed on the same product, good correlations should be observed. 

Triphosgene, a safe and stable crystalline solid substitute for phosgene [53, 148], is successfully utilized in the sequential synthesis of unsymmetrical ureas also bearing chiral amino acid derivatives, without any need to purify the intermediates [507]. 

Equation 11.1, which we applied to LLE, applies to any phase equilibrium, so it must apply to LSE, with phase 1 being the liquid and phase 2 being the solid. Substituting the definition of the fugacity in terms of the standard state fugacity and solving for the mol fraction of dissolved solid, we find... 

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