Depends on what you want to use it for. Pure aliphatics are all comparable acidity, with formic a little higher; add chlorines in the 2-C position and then you get a strong acid (trichloroacetic, for example); or use an activated aromatic structure (p-toluenesulfonic acid, for example). If you're intending this for a skin-topical formulation, toxicity would be a concern, in addition to acid effects! By "dissociate itself", do you mean that it does not dimerize in non-aqueous solution (since organic acids would tend to)? Or do you just mean, will ionize?