[Leong Jun Xing]

Hi Guys. I need guidance from you all. I am currently trying to adding 2-aminoethyl hydrogen sulfate into graphene oxide (GO). There are -OH and -COOH on graphene oxide. In order to do so, firstly I need to convert the GO into acyl chloride GO by using thionyl chloride, SOCl2. My reaction are as below:

1.Graphene oxide added into SOCl2 (add in DMF as catalyst) and stir under reflux at 70C for 24 hours.
2. Excess SOCl2 was removed by distillation and acyl chloride GO is obtained.
3. In order to replace the Cl with the 2-aminoethyl hydrogen sulphate, acyl chloride GO and 2-aminoethyl hydrogen sulphate should be added into DMF solvent. However, I found out that 2-aminoethylhydrogen sulphate cannnot dissolved in DMF solvent.

My questions are:
1. is that I can dissolved 2-aminoethyl hydrogen sulphate in water first, then only I add the 2-aminoethylhydrogen sulphate into acyl chloride GO solution (in DMF) because acyl chloride GO cannot dissolve in water too.
2. Is that I can carried out the reaction in water although acyl chloride GO cannot dissolved in water? Or is that I can carried out the reaction in DMF solvent although 2-aminoethylhydrogen sulphate cannot dissolved in DMF? In other means, for reactions to occur, is that both reactant should be well dissoved in solvent?

Hope to receive replies from you all. thank you.

[TheUnassuming]

The ideal is of course that all components in a reaction are in solution, but this doesn't always happen. 
I wouldn't use water in general around an acid chloride, so try first using DMF and just see if enough of the amino goes into solution to allow the reaction to proceed.  You might have to heat/sonicate the reaction a bit, but more than likely it will proceed (admittedly slowly) as long as you don't get decomposition.
Other solvents can be used as well, but generally stay away from protic solvents.   

[SDVENHI]

A simple solution would be to avoid the use of the acid chloride altogether.  You should be able to use EDCI/triethylamine/NHS plus your amine in DMF at room temperature.  I've used these conditions to conjugate taurine with a DMF-soluble carboxylic acid and it worked well enough (>60%)
If you still want to use the acid chloride in DMF (check that there are no reactions between acid chloride and DMF) it should be possible to enhance the solubility of the amine in DMF by adding an equivalent of a tertiary amine (triethylamine, diisopropylethylamine, etc.).  I usually add 2-4x equivalents of tertiary amine to ensure that the HCl released during the coupling is scavenged.