Is it possible for me to get a Chinese visa in Bangkok?

You can try to apply it in the Bangkok Chinese embassy, but it is not assured that you can get it. You can contact them for confirming in advance.
The following materials are required: a valid passport and a photocopy of its data page, an application form affixed with a recent color photo, the original and photocopy of your entry permit for Thailand, round-trip tickets receipts, hotel booking records for China and other materials the embassy requires.

Alternatively, you can join in a tourist group and apply for a group type through travel agencies.