A patent is an exclusive intellectual property right granted for an invention. To be patented, the invention (a product or process) must provide a new way of doing something or offer a new technical solution to a problem. To get a patent, the inventors must disclose technical information about the invention to the public in a patent application. (Definition adapted from the World Intellectual Property Organization).
Searching for chemical information in patents can be notoriously difficult because patents primarily serve as legal documents rather than as a source for sharing scientific knowledge. Some inventors (and patent attorneys) deliberately use obscure language in their patent applications to discourage reading. The patent classification and keyword system can also be difficult to navigate.
For chemical processes and technology, SciFinder searches a wide scope of patents. Especially for general searching, I recommend starting here.
For more information about patents, visit the Patents and Trademarks guide linked below. If you need to do a deep dive into the patent literature, I would encourage you to contact me so that I can help.