Does using a colon (:) correctly combine these 2 sentences?

Question

I'm asking about the following construction. I'm not sure whether the way I use a colon to combine my sentences is correct.

Here, I would like to summarize the reasons for my extension
request: as necessity of additional time for rectifying the
algorithms, lengthy literature survey than expected and etc.

Answer 1

There are a few problems with your sentence. The colon is only one.

Here, I would like to summarize the reasons for my extension request : as necessity of additional time for rectifying the algorithms, lengthy literature survey than expected and etc.

The first problem is that there is no space before the colon, only after the colon.

The second is that the list of reasons is likely to be too long, which will make the sentence difficult to read and understand. I'd recommend that you use a different kind of list. For example:

I have four [However many there are] reasons for requesting an extension. First, I need more time to rectify the algorithms. Second, reviewing the literature is taking much longer than I expected. Third, yada yada yada. Fourth, blah blah blah.

You can also choose to use a bulleted list instead:

I have four reasons for requesting an extension:

• I need more time to rectify the algorithms.
• reviewing the literature is taking much longer than I expected.
• Yada yada yada.
• Blah blah blah.

Answer 2

Colons are used to introduce a phrase that explains what previously said, and a list.

I like the old manga series: UFO Robot Grendizer, Mazinger Z, and Steel Jeeg.

Probably, "as necessity of additional […]" should be "the necessity of additional […]"; also "lengthy literature survey than expected" should probably be rephrased.

Answer 3

You would use a colon or semi-colon when joining 2 independent clauses. But in your example, the second clause

as necessity of additional time for rectifying the algorithms, lengthy literature survey than expected and etc.

refers to the reasons for summarizing mentioned in the first clause. Also the first clause is not independent (able to stand by itself). So you should use a comma instead.

Here, I would like to summarize the reasons for my extension request, due to the necessity of additional time for rectifying the algorithms, lengthy literature survey than expected and etc.

I used due to because the second clause is explaining or expanding on the first clause.