نتایج جستجو برای: addition of ethyl alcohol to triethyl propargl ammonium bromide
تعداد نتایج: 22182423 فیلتر نتایج به سال:
In the title compound, C(6)H(16)N(+)·C(7)H(5)O(4) (-), the hy-droxy groups of the 3,4-dihy-droxy-benzoate anion form O-H⋯O hydrogen bonds to the carboxyl-ate groups of two adjacent anions, generating layers propagating in the ac plane. The triethyl-ammonium cations lie between these layers, forming N-H⋯O hydrogen bonds to the carboxyl-ate groups of the anions. The structure is consolidated by w...
Probably the first studies of the pharmacology of quaternary ammonium compounds were made by Crum-Brown and Fraser in 1868. Burn and Dale (1915) found that, unlike nicotine, tetraethyl-ammonium chloride blocked autonomic ganglia without noticeable initial stimulation. Barlow and Ing (1948a and b), Paton and Zaimis (1948a and b), and Balaban et al. (1949) studied the properties of some chemical ...
abstract tasks nowadays are at the center of attention in sla research. task types is one of the critical issues in this regard, their effectiveness and suitability to any particular context, their characteristics and the result they yield are among some of these issues. on the other hand, discourse markers (dms) have been very much investigated and their effectiveness in conveying the meaning...
abstract the primary purpose of this study was to explore the actual practices and cognitions of two groups of iranian eap teachers, i.e. language teachers and content teachers, with respect to teaching reading-comprehension and vocabulary. to this end, tehran university of medical sciences which authorizes both groups of teachers to teach eap courses was selected as the context of the study s...
the current study examined iranian undergraduate efl students’ willingness to communicate with regard to their vocabulary knowledge. in general, participants were somewhat willing to communicate in english. the total mean score of 730 university students’ perception of willing to communicate was 83.53 out of 135. results, regarding four parts of willingness to communicate, revealed that part...
abstract: the present study is an attempt to find out cultural exophoric references in iranian high-school elt textbooks and touch stone series to compare the frequency of occurrence of such references in these books. the purpose is to find out which of the series of the books under investigation impose a greater referential burden on efl learners as far as their reading comprehension of the ...
abstract: the present study was undertaken to investigate whether 1) there is any significant correlation between iranian efl/eap learners’ l2 writing proficiency and their willingness to communicate, 2) there is any significant difference between efl and eap learners in terms of willingness to communicate, 3) there is any significant difference in wtc of iranian efl/eap learners with 1- nati...
monumental changes occurring on a daily basis have altered the world into a global village of expanding technology and shrinking geography in which preparing language learners for intercultural communication seems to be a sine qua non for modern language education. employing a cross-sectional design in its first phase, this study investigated the intercultural sensitivity and language proficien...
Binding studies of cationic detergents such as cetyltrimethyl ammonium bromide, Cetyl pyridinium bromide and dodecyl trimethyl ammonium bromide with β Lactoglobulin were carried out by equilibrium dialysis, ultraviolet difference and circular dichroism techniques at 25 C. Binding isotherms at pH 5·0, 7·0 and 9·0 show cooperative binding at all concentrations of detergents and the number of avai...
In the preceding papers (1, 2) the preparation and properties of sulfonium salts of methionine were described. The ease of formation of the methylsulfonium salt and the solubility properties of its phosphotungstate suggest utilization for the characterization of methionine in amino acid mixtures, since the phosphotungstates of other a-amino acids are readily soluble in cold aqueous alcohol whil...
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