Additions and Corrections - Elimination Reactions of N-(2-p-Nitrophenyl)ethyl) alkyl-ammonium Ions by an E1cB Mechanism

1983 ◽  
Vol 105 (19) ◽  
pp. 6195-6195
Author(s):  
James Keefe ◽  
William Jencks
Keyword(s):  
Ammonium Ions ◽  
Elimination Reactions ◽  
Alkyl Ammonium

Hydratation und hydrophobe Wechselwirkung der Ionen in Polyelektrolyten mit einer Folgerung bezüglich der biologischen Membranen

1969 ◽  
Vol 24 (4) ◽  
pp. 375-377 ◽  
Author(s):  
G. Zundel ◽  
A. Murr
Keyword(s):  
Sulfonic Acid ◽  
Pure Water ◽  
Water Structure ◽  
Water Molecules ◽  
Pure Liquid ◽  
Ammonium Ions ◽  
Alkali Ions ◽  
Stretching Vibration ◽  
Polystyrene Sulfonic Acid ◽  
Alkyl Ammonium

The OH stretching vibration of the water molecules in membranes of salts of polystyrene sulfonic acid is investigated by IR spectroscopy. In the series of the alkali ions anomalous behaviour of the position of this band is to be seen. If one compares the position of this band with the corresponding one in pure liquid water this anomality is to be understood like follows: From Li⊕ to Cs⊕ in a progressing degree the molecules of water are not still attached between cation and neighboring anions, but they are present as network of „pure“ water structure cross-linked by hydrogen bonds in the neighbourhood of the ions. A similar situation but to an even greater extend is found in the presence of alkyl ammonium ions. These ions are interacting more strongly with the - SO3⊝ ions. The reasons for this are given. By these results it is understandable that in biological membranes the alkyl ammonium group of the lecithins and sphingomyelines - as postulated by FINEAN - are turned away the surface inwardly in the membran. In the end the different hydration behaviour of the Na⊕ and K⊕ ions is discussed.

An energy-resolved study of the fragmentation reactions of alkyl ammonium ions

1994 ◽  
Vol 72 (11) ◽  
pp. 2205-2211 ◽  
Author(s):  
Nancy L. Bosma ◽  
Alex. G. Harrison
Keyword(s):  
Bond Cleavage ◽  
Centre Of Mass ◽  
Stable Secondary Structure ◽  
Ammonium Ions ◽  
Energy Profiles ◽  
Compound C ◽  
Fragmentation Reactions ◽  
Alkyl Ammonium ◽  
Homolytic Bond Cleavage ◽  
Alkane Elimination

The unimolecular metastable ion and low-energy collision-induced fragmentation reactions of alkyl ammonium ions RnH4−nN+ (n = 2 to 4, R = n-C3H7 and n-C4H9) have been studied and breakdown graphs expressing the % fragment ion abundances as a function of the centre-of-mass collision energy have been established. The dialkyl and trialkyl ammonium ions fragment primarily by olefin ([R − H]) elimination or by formation of the alkyl ion R+ (with rearrangement to the more stable secondary structure). By contrast the tetraalkyl ammonium ions show both elimination of [R − H] and elimination of an alkane, which is C5H12 for the propyl compound C7H16 for the butyl compound. The results are interpreted in terms of competition between heterolytic bond cleavage to form a [R+---NH4−nRn−1] complex and homolytic bond cleavage to form a [Rn−1H4−nN+•---•R] complex. The former complex fragments either to form R+ or undergoes internal proton transfer to form Rn−1H4−nNH+ + [R − H], while the latter complex fragments by alkane elimination resulting from attack of R• on the α-CC bond of the alkyl group. For the propyl ammonium ions plausible potential energy profiles are established which show that the former complex is favoured for n = 2, 3 while the two complexes have similar energies for n = 4.

Morphology of Poly Amide Nanocomposites Characterized by Transmission Electron Microscopy (TEM) and Electron Spectroscopic Imaging (ESI).

2001 ◽  
Vol 7 (S2) ◽  
pp. 502-503
Author(s):  
W. Heckmann ◽  
F. Ramsteiner ◽  
Ch. Mehler
Keyword(s):  
Building Blocks ◽  
Layered Silicates ◽  
Ammonium Ions ◽  
Melt Mixing ◽  
Sodium Potassium ◽  
Modified Montmorillonite ◽  
Transmission Electron ◽  
Organically Modified ◽  
Alkyl Ammonium ◽  
Potassium Magnesium

The introduction of organophilic layered silicates into a polyamide matrix significantly improves stiffness and strength [1,2]. Two methods are known to prepare such nanocomposites. For both methods cations such as sodium, potassium, magnesium or calcium, located in the interlayer galleries of the layered silicates must be exchanged by quaternary alkyl ammonium ions containing at least one alkyl chain and so rendering the originally hydrophilic into an organophilic silicate. in the insitu-method monomeric caprolactam is intercalated between the modified silicate interlayers and subsequently polycondensated to polyamide. By this method the silicates can be broken down into their nanoscale building blocks as can be shown by TEM and ESI (Fig. 1). Another more direct possibility to delaminate the silicates is melt mixing in an extruder. with both methods similar degrees of delamination can be achieved.This paper presents some of our morphological results on polyamide containing organically modified montmorillonite.

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