Are the following sentences correct?
1. In this book, we do find some differences between the two cultures.
But instead of dwelling on the differences, the author presents lengthy discussions on things they have in common, of which why their loyalty to work is placed emphasis on is most thoroughly touched upon.

2. In this book, we do find some differences between the two cultures.
But instead of dwelling on the differences of the two cultures, the author presents detailed discussions on the similarities of them, and what is touched upon (the) most is why both of which place so much emphasis on their loyalty to work.

Are these sentences correct in grammar? If not, please correct my mistakes.

Question

Are the following  sentences correct?
1. In this book, we do find some differences between the two cultures. 
But instead of dwelling on the differences, the author presents lengthy discussions on things they have in common, of which why their loyalty to work is placed emphasis on is most thoroughly touched upon.

2. In this book, we do find some differences between the two cultures. 
But instead of dwelling on the differences of the two cultures, the author presents detailed discussions on the similarities of them, and what is touched upon (the) most is why both of which place so much emphasis on their loyalty to work.

Are these sentences correct in grammar? If not, please correct my mistakes.

Answer

They start off well! ;^)
In the first sentence, you should delete the 'do' unless you are stressing that there are differences in THIS book (and by implication not in a previous book, or elsewhere)
e.g. we didn't find it there, but we do find it here.

The first version of the second sentence would be completely unreadable without the second one to give guidance as to what you were trying to say! But even then, I'm not sure. Who is placing emphasis? The book, or the cultures? I can't easily rewrite it without resorting to a structure that is more similar to your second version.

But instead of dwelling on the differences between the two cultures, the author presents detailed discussions on the similarities between them, and what is touched upon the most is why both of them place so much emphasis on their loyalty to work.

'place so much emphasis on their loyalty to work seems somewhat laboured to me though. 
Doesn't having loyalty to work imply that there is a strong emphasis on it?