Yurii V Geletii I think that a large proportion of the questions on RG are poorly expressed, lack detail, and often are full of appalling grammar and spelling mistakes. One usually has to question the questioner...

And then there are the questions that attract a lot of answers... I posed this one a while ago:

https://www.researchgate.net/post/Is_the_number_of_replies_to_an_RG_question_inversely_proportional_to_the_usefulness_of_said_replies

exploit the hydrophilic lipophilic balance of the actives.

Ravi Shantilal Parmar Without some knowledge of the materials you're trying to dissolve then it is difficult to help you. In general chemical terms then 'like prefers like'. HgS, for example, is very insoluble in virtually every liquid.

In your application area (pharma) then size reduction to nano, encapsulation, and the use of the hydrochloride salts have all been utilized. Also use of FDA approved surfactants such as Tween or Span.

Also many of the solvents you mention are incompatible with biological systems.

Dear Sir

Please check the following link may be useful for you

https://www.sciencedirect.com/topics/engineering/dimethyl-sulfoxide

Hi Ravi Shantilal Parmar, It is known that like dissolves like. However, surfactants e.g. CTAB can dissolve both hydrophilic and hydrophobic compounds due to the presence of both heads & tails together within the molecule. Also, aqua regia is known for its deep dissolving effect especially for gold and similar metals. As your direction lies in pharmaceutics, then you advised to use only pure water to be safe for biological cells, and if not soluble, then you should find another application for your compounds away from pharmaceutics e.g. industrial applications.

N.B. Do not forget ultrasonic as a powerful mechanical/physical technique in dissolving chemical compounds in a suitable solvent.

Ravi Shantilal Parmar In order to answer your question you have to clarify what is the meaning of "dissolve something in a solvent." What is a solubility? What happens in the process of dissolution?

Mohammad Hegazy Is gold as a metal, Au(0), soluble in aqua regia? Do "surfactants" make "solutions?" "like dissolves like?"

Alan F Rawle 'like prefers like'. NaCl is well soluble in water. Is NaCl like water?

Yurii V Geletii Yes, challenging and provoking questions. You'll be aware, as a chemist, of the saying 'like prefers like' especially in organic chemistry. And ionic bonding and covalent bonding are totally different entities. The 'like' between NaCl and water is that they're both polar compounds and the dissociation in solution of NaCl leads to Na+ and Cl- ions. Another 'like prefers like' comparison in a molten mix is the high 'solubility' of NaCl in KCl.

I think we're both on the same page when we're needing more information from the poster in terms of the materials he wants to solubilize - I was thinking of organic materials. And HgS would be soluble in strong acid with the evolution of H2S but reactivity isn't really solubility... Or is it? The reaction between NaCl and water to separate the ions involves energy...

Yes, Alan F Rawle , you correctly understood my post. I just wanted to illustrate that some "simple" questions are often much more complex, than they look like. Therefore, we should always use correct terminology or clarify how do we understand the meaning of used terms. I commonly consult "IUPAC Gold Book" for recommended terminology. However, there are evident mistakes in it as well. I don't expect that my questions should be discussed in details. My goal was to demonstrate that the answers might not be related to the original not very clearly formulated question. I may ask about apples, the answers might be about oranges.

Vad Pérez Seems like a cat joke to me....

Yurii V Geletii I think that a large proportion of the questions on RG are poorly expressed, lack detail, and often are full of appalling grammar and spelling mistakes. One usually has to question the questioner...

And then there are the questions that attract a lot of answers... I posed this one a while ago:

https://www.researchgate.net/post/Is_the_number_of_replies_to_an_RG_question_inversely_proportional_to_the_usefulness_of_said_replies

Yes, Alan F Rawle , a large proportion of the questions on RG does not fit minimal requirements from a professional point of view.

I also posted several questions about the quality of posts on RG

Dear Yurii V Geletii I know what you mean but as you can notice, the questioner did not provide detailed data and his data were not specific about certain compounds from his question, so I decided to provide a short general image about the solubility and some useful rules which maybe benefit him or any other RG users.

Mohammad Hegazy One important point - surfactants wet a material by bridging insoluble phases. They do not dissolve or even encourage dissolution.

So, still we have no answer from Ravi...

As a generall comment about solubility:

1. some salts like BaSO4 are not soluble- this is the end.

2. sometimes ph plays important role

3. Different solvents like sulfolane, NMP, DMF, THF should be studied

4. in some cases supercritical fluids could be used.

regards,

GB

Qasim Abdulkarem Al-Obaidi What is the "liser" technique? Google search asks "laser?" If you misspelled, this is not professional. I apologize, if liser technique does exist. "vibration technique????"

I think mixture of DMSO and water can partially soluble my compounds.

But still i am phasing some issue in purification.

Grzegorz Boczkaj

• BaSO4 is soluble in concentrated sulfuric and hydrochloric acids
• pH is shown thus and, yes, changes can cause solution due to reactivity
• Solvents such as NMP, DMF, THF, DMSO, MeOH are incompatible with biological media and it's difficult to see how they could be applied in a biological/pharmaceutical setting
• Yes, supercritical fluids could be considered but see the bullet point immediately above

The poster needs to help us to help him by being more specific

Mr. ravi first check the polarity of your compound and choose solvents accordingly and specify the use of your solution so that one can suggest batter option for you

Mr Ravi ,simple concept like dissolve like, so please check nature, polarity, ionic or covalent character of compounds

Dear Ravi Shantilal Parmar ,

did you test (applying) any high(er) pressure (condition), since, apart temperature[1], the maximum effective solubility of a substance[2] depends, also, on the pressure.

1. Apart temperature, you, already, tested, the final maximum solubility of a substance depends, also, on the pressure, pH, solution processing-time, mechanical power, solvents' mixture, etc.

2. I agree with Alan F Rawle, "The poster needs to help us to help him by being more specific", and Yurii V Geletii, also. Say a specific case(s, list).

Dear Ravi Shantilal Parmar seems that with your ill-defined question you kept several highly qualified RG members busy on this thread. You cannot expect to get "real" answers to your question without providing more details. Are you e.g. talking about organic or inorganic compounds? If a compound is insoluble in a certain solvent then it remains insoluble. If it has a low solubility, you can try continuous extraction e.g. using a Soxhlet apparatus. By the way, are you still interested in having your question answered or not?