Is it a good practice to use plain text for derivation of Keys? I have a question regarding the derivation of keys in crypto.
Is it a good practice to use the plain text (in form of hashes) for derivation of keys ? these keys will be used for encryption of the same plain text later on.

What are possible drawbacks of the same if any ? 

Thank You in advance.

Edit 1: For example 

I have a plain text say X

The hash, H = Random Text + X;

Key, K1 = Initial Key XOR H;

Cipher C = Enc (K1, X)

So it is a good practice to use the plain text as shown in above manner for key generation and encryption ? 
what are the drawbacks of the same.

Edit 2
The other party will receive 

Cipher C along with C1 = Enc(K0, Hash)

So that in order to decipher, apply Dec(K0, C1) = Hash

K1 = Hash XOR K0

and then PT = Dec(K1, C)

Thank You.
The hash can only be calculated once you know the plaintext (and, in your case, the Random Text as well). If you already know the plaintext there is no need to know the key anymore.

So basically you have a scheme here that either offers no security at all, or a scheme that is impossible to decipher, even for the intended users (apart from guessing the plaintext).



In your update you show that you now wrap and unwrap the hash. That would make this scheme feasible, but it would still leak information. If you have identical plaintext then you will also have identical ciphertext, unles you change Random Text each time. You also haven't specified an IV.



If you have a random number generator already then it is much easier to calculate $K_d = KDF(K_{master}, Salt)$ and then $C = E(K_d, P)$. Or you could just use a random IV and (authenticated) encryption.

There is a strong feeling that you've deviced your own protocol because you are unfamiliar with common techniques. That's never a good idea.