Could you please tell me which sentence is correct?

1. I'll call you later when I read it.
2. I'll call you later after I read it.

Another question is here. Would you please check this sentence for me, too?

I believe that this project will generate the profits for our company.
(the profits? the profit? or, a profit??)

I'll appreciate it very much if you help me with them.

Mmm... I'm not sure about the second one. To me, I'd rather use:

I'll call you after reading it. 
I'll call you after having read it.

In the last one, you can use either "profits" or "a profit". Remember that "the profit" will refer to something specific. Compare:

I believe this project will generate the profits we urgently need for our company.

Hope this helps! Emotion: smile

In this particular case I would say the present perfect is possible as well. " I'll call you after I have read it".
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Thanks for your response!

For the second one, it sounds much better if I use the ones you wrote as examples.

According to your explanation, can I use "profits" without articles in the last one?
I don't want to tell what kind of "profits" here in this sentence.

Thanks again for your help Emotion: smile
 maj's reply was promoted to an answer.
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In the sentence:

I believe the project will generate profits for our company.

You talk about a general profit. Just what you intend to do: not to mention what kind of profits.

Bye. Emotion: smile