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I saw a Youtube video which showed that cotton (cellulose) dissolves in deep blue solution of tetramine copper made by adding 20% ammonia in copper carbonate salt. I tried to replicate the process using $\ce{CuSO4}$ and copper chloride. None worked. Where have I gone wrong?

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As @iad22agp states, it is not sufficiently alkaline. Schweizer's reagent is tetraamminediaquacopper dihydroxide, $\ce{[Cu(NH3)4(H2O)2](OH)2}$. See Schweizer's reagent.

That is not Doktor Schweizer, I presume.

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You might want to check the pH - you would have a less basic solution using copper sulfate or chloride than you would get from copper carbonate, and that could be less effective in dissolving the cotton. Also, your particular sample of cotton might behave differently from others, such as that used in the video.

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There should be no anions exept OH- present.

made by adding 20% ammonia in copper carbonate salt.

is wrong, using CuSO4 is even wronger.

You have to precipitate Cu(OH)2 and wash the

precipitate thoroughly, a very tedious operation.

According to a IG Farbenindustrie Patent You

throw copper pieces in > 25 % Ammonia

(cut from electrical wire) and percolate

with oxygen or air. When using air, you have to

maintain temperature under 8 °C. This needs days

until "ready" but has the advantage that the

reagent is pure without cleaning operations.

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  • $\begingroup$ Is there any reason this is formatted like a cinquain? $\endgroup$
    – andselisk ♦
    Commented Jan 7, 2021 at 8:31