this depends on the media of your reaction mixture. and the nature of your reactant whether hygroscopic or not .so it's possible to happen .

Hello Hirbod - ha ha a very academic Q.

Well - an aq solution (with high ion strenght) can theoretically remove water from the reaction if the reactants not are solvatized by water, but are in a suspension or ion pair mode. I will vote for the suspension conditions, and that is not an aq solution!

Have a nize day and good luck

TKO

This is an interesting question, especially for thermo-responsive molecules. You can dehydrate small molecules and polymers under the assistance of outer forces, e.g., heating or pH tuning.

Good morning.

Your question is very interesting but difficult objective response. Could you provide more information about what you want to do?

NaA zeolite membranes were used for pervaporation dehydration of ethylene glycol (EG)/water mixtures. The reduction of operating temperature is effective to improve membrane stability for operating at high feed water content (e.g. 30 wt.%). A permeation flux of 4.03 kg m−2 h−1 with separation factor of >5000 is achieved at 120 ◦C for the separation of the solution with 20 wt.% water content.

Please, consult:

Chemical Engineering Research and Design, doi:10.1016/j.cherd.2011.12.003

I too would like more information. I am tempted to say no as many anhydrous compounds like acid anhydrides or inorganic salts typically react readily with water. Addition of acetic anhydride to glacial acetic acid is used to remove the water for organometallic synthesis. Some of the above example suggest otherwise, so more information on your specific system could be helpful. 

you can do condensation reaction in aqueous solution, usually with low yield. for example EDC  (1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride) is used to make amid bonds within R(1)-COOH and NH2-R(2). And you can also could find some reaction using water as a solvent if you looking for "green chemistry". 

here is a link for EDC

https://www.piercenet.com/instructions/2160475.pdf

Yes, it is possible to do a condensation reaction under aqueous conditions. For example amide bond formation in aqueous solution can be carried out with EDCI as previously stated. Another useful reagent is TSTU (N,N,N′,N′-Tetramethyl-O-(N-succinimidyl)uronium tetrafluoroborate). Both these reagents form highly reactive intermediates with carboxylic acids that then undergo nucleophilic acyl substitution. In addition, pre-formed NHS esters can also be used under aqueous conditions as they are stable for several hours at neutral pH. Yields will vary depending on the pH. Typically, the higher the pH the lower the yield. In addition a mixed solvent system may give higher yields by decreasing the water content (ex: water/dioxane or water/DMF). There are many variables you can play with.

Because amines are usually more nucleophilic as water, reaction is possible. For instance, cyclam and cyclen reacts with glyoxal in water media to cyclic aminals - fast and irreversible

For most such reactions the dehydration aspect is inherently reversible. The reaction still takes place in water but the distribution of products may make isolation difficult as the reactions do not often go to completion. The presence of water as an active mass drives the reaction in favour of the reactants. Condensation may still occur but under thermodynamically equilibriating conditions it won't go to completion.

If the dehydration reaction is effectively irreversible then it will easily occur in water. The reversibility of the reactions will depend on the relative energies of the system. If the product is insoluble in water then the lattice energy will drive the reaction to completion.

One of Jonathan Winters Quotes "Nothing is impossible. Some things are just less likely than others.".

My answer is in accordance with the words of your question. Dehydration indicates the removal of the components of water (H, OH). The OH is a bad leaving group & that is why it is protonated with an acid to become  (-OH2+)  which is a good leaving group. Once this leaves, there are 2 possibilities: elimination of H+ from an adjacent C or nucleophilic substitution. If there is an aqueous medium, the substitution path is favored (since water will act as nucleophile) especially at moderate temperature. Primary amines, RNH2 , undergo nucleophilic addition with " carbonyls i.e. aldehydes or ketones" to give carbinolamines which then dehydrate to give substituted imines. The reaction is usually done in an acidic buffer to activate the C=O and facilitate dehydration but if water is a medium, it will mess up everything!

In short, the suggested reaction is less likely to occur according to our present knowledge!

Thanks everybody.  >:)