In some contexts, the words are close synonyms, but not in all.
Both particular and specific mean “distinguished in some way among others of the same kind,” so the following sets of statements would have the same meaning:
Do you have a particular company in mind?To me specific has a more formal connotation than particular. Although the meanings are identical in these examples, I’d probably choose specific in the business context and particular in the leisure context.
Do you have a specific company in mind?
Do you have a particular movie you want to see?
Do you have a specific movie you want to see?
Specific has several technical uses. It can mean “pertaining to a distinct species of animals or plants. For example, “Gaspard Bauhin, a Swiss botanist of the late 16th and early 17th centuries, designated plants by a generic and a specific name.” In medicine, a “specific remedy” is a remedy supposed to act on a particular ailment or part of the body.
In the study of logic, a statement that is true of all of a group is a universal statement, while a statement that is true of a certain kind of thing is a particular statement.
For example, “All fish live in water” is a universal statement; “Goldfish are often kept as pets” is a particular statement.
In general usage, the two words are used interchangeably when referring to plans:
Did you ever have any particular plans at the beginning of your career, any particular vision of where performing would take you?
The Barons did the show and, as an amateur group without particular plans,
Asked about the future, Paul Simon says he has no particular plans.
Source: Daily Writing Tips