Dear Amir,

Generally, alkylation of graphine oxide is carried out via two steps: nucleophilic addition of n-butyllithium (n-BuLi) to the GO sheets and a subsequent coupling and etherification reaction of the intermediates (Bu-GO)n−Lin+ and alkyl halide (such as alkyl bromide) leading to functionalized GO:

http://onlinelibrary.wiley.com/doi/10.1002/macp.201100658/abstract

Reaction of GO with alkylamine is expected to form the corresponding ammonium salt of GO (ionization of the carboxylic groups present in GO) and it is hard to believe that alkylation of GO can take place via this method.

Please see GO structure illustrated in the following link:

https://arxiv.org/ftp/arxiv/papers/1212/1212.6413.pdf

https://encrypted.google.com/search?q=graphene+oxide+structure&newwindow=1&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi2wc2av9jOAhVGvhQKHRVcA6wQsAQIMA&biw=1366&bih=667

Regarding the FTIR peak with a frequency of 3400 CM-1, it may correspond to the ammonium function (-NH2- +).

Hoping this will be helpful,

Rafik

thank you

but whats the reason that the peak around 3400 has been sharpened and intensified?

Dear Amir,

The presence of the alkylammonium moiety of the resulted salt is responsible for the sharp and intense peak at frequency of 3400 CM-1.

Rafik

Thanks prof. karaman

is there any citable reference that confirm this?

The following link contains FTIR spectra of several ammonium salts.

https://encrypted.google.com/search?q=ftir+of+methyl+ammonium+salt&newwindow=1&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjRqIbD5drOAhVD6RQKHdPEDQEQsAQILQ&biw=1366&bih=667

In order to confirm what I proposed, take a quantity of your product, acidify with HCl, wash with water, filter, dry and take FTIR. The FTIR for the material after acidification should be identical to that of the starting material (graphene oxide).

Rafik