Patents describe an innovation as a part of obtaining intellectual property protections. Patents provide information that may not have been published in other venues like journal articles. For chemists and chemical engineers, patents can be a particularly valuable way find chemical process information that is designed for active use in industry. ACS provides an overview of the patenting process in the chemical industry.
Patent searching can be a little complex, because patents use very stylized language, and because they are often filed in particular nations (e.g. all US patents are filed with and disseminated by the US Patent and Trademark Office, while Japanese patents are filed and disseminated by a similar organization in Japan) but several tools can help you find them more efficiently.