that of

[WilliamTaft]

The definitions of that in Longman Contemporary:

1 used to refer to a person, thing, idea etc that has already been mentioned or is already known about - I wish you wouldn’t say things like that.
2...
3 formal used to refer to a particular person or thing of the general type that has just been mentioned - His own experience was different from that of his friends.

Is there any difference between the two?

 

[tedmc]

You have already stated the difference, i.e. the second being one of a general type/category.

 

[Tarheel]

The way it's used in those examples is certainly very similar. Are you confused about how to use "that"?

It's one of the most commonly used pronouns, so you should certainly get a lot of practice either using it or seeing it being used. And that might be more important than seeing what is said about it in a dictionary.

 

[Friar Lawrence]

The definitions of that in Longman Contemporary:

1 used to refer to a person, thing, idea etc that has already been mentioned or is already known about - I wish you wouldn’t say things like that.
2...
3 formal used to refer to a particular person or thing of the general type that has just been mentioned - His own experience was different from that of his friends.

Is there any difference between the two?

There is a big difference in the grammar of these two uses of that. In 1, that is an unmodified demonstrative pronoun; what that refers to will be, or should be, contextually determinable, though it will be expressible in different ways:

I wish you wouldn't say things like [that = what you just said / your last comment / etc.].

In 2, that is a pronoun modified by a prepositional phrase; it is replaceable by a specific expression determined by the immediate syntactic context. In the sentence His own experience was different from that of his friends, the expression for which that stands as a pro-form is the definite noun phrase the experience.

His own experience was different from [that = the experience] of his friends.

Note that, with the that of 1, this can often be used as an alternative to that: I wish you wouldn't say things like this. Substitution with this is never possible with the usage of that found in 2: His own experience was different from this of his friends.

 

[teechar]

In 2, that is a pronoun ...

and

Substitution with this is never possible with the usage of that found in 2: His own experience was different from this of his friends.

I take it you meant to write "3" instead of "2".

 

[Friar Lawrence]

Yes, Teechar -- thank you for correcting that. There are only two examples in the OP, but they are labeled "1" and "3." Where I wrote "2," it was in reference to "3."