3401-74-9Relevant articles and documents
Ultrasonic Relaxation and Carbon-13 NMR Studies of Dialkylammonium Chloride Micelles
Lang, Jacques
, p. 992 - 998 (1982)
Ther cmc values of several dialkylmethyl and dialkyldimethylammonium chloride surfactants, with a number of carbon atoms per alkyl chain, nc, between 6 and 12, have been measured by conductivity and ultrasonic absorption techniques.The results agree with earlier cmc measurements for dialkyldimethylammonium chlorides with nc equal to 8, 10, and 12.The aggregation number of dihexylmethylammonium chloride has been determined by 13C NMR.The value of 6 has been found, which is in good agreement with the values obtained for monoalkyl chain surfactants.The kinetic study of the fast exchange process occurring in micellar solutions has been carried out by means of ultrasonic absorption methods on aqueous solutions of dialkylmethylammonium chlorides with 6, 7, and 8 carbon atoms in each alkyl chain.The relaxation time τ1 which characterizes this fast process increases as the alkyl chain length increases as for monoalkyl surfactants.The τ1 values are much closer to those found for straight-chain surfactants with 6, 7, and 8 carbon atoms than those found for straight-chain surfactants with 12, 14, and 16 carbon atoms.The kinetic results are discussed in terms of Aniansson and Wall's theory.
Powerful tailoring effects of counterions of ammonium surfactants on the phase transitions of solvent-free DNA thermotropic liquid crystals
Gu, Jingjing,Liu, Han,Luo, Xiliang,Qu, Yang,Wu, Zhongtao,Zhang, Lei
, (2021/06/15)
Solvent-free DNA-surfactant thermotropic liquid crystals (TLCs) are new developed soft biomaterials in recent years. The phase transition behaviors of these DNA TLCs could be regulated by the chain lengths of used double chain surfactants. While, the impact of counterions of ammonium surfactants on the phase transitions of DNA TLCs is still not clear. Herein, a series of ammonium surfactants with different counterions were prepared and put into use of fabrication of DNA TLCs. With inorganic counterions, the resulted DNA materials exhibit distinct decrease on the thermodynamic stability of LC states along with the size increase of counterions, while, the use of planar p-toluenesulfonate as counterion leads to remarkable increased LC thermostability for the resulted DNA material, due to the different interaction between counterions and surfactant layers. These observations indicate that the LC property of DNA-surfactant complexes could be conveniently tailored by using surfactants with designed counterions, providing a new strategy for designing advanced solvent-free biomaterials.
Process for preparing 2,2'-azobis(2,4-dimethyl-4-methoxypentanenitrile)
-
, (2008/06/13)
A process for the preparation of 2,2'-azobis(2,4-dimethyl-4-methoxypentanenitrile) in improved yields with improved filtering characteristics, said process comprising reacting 2-amino-2,4-dimethyl-4-methoxypentanenitrile with a metal hypochlorite in the presence of water, a quaternary ammonium surface active compound and ionic bromide wherein the equivalent ratio of ionic bromide to surface active compound is 0.4:1-4:1 at a temperature of about -10° C. to about 30° C., and recovering 2,2'-azobis(2,4-dimethyl-4-methoxypentanenitrile) from the reaction mixture.
