All three can refer to a specific person or thing. He had especial/special/particular requirements for the car that he was going to buy. 'Especial' and 'special' can also refer to something that is set apart from others, usually in a good way. "He was a special student, with a tremendous talent for math,." You would not use 'particular' in this case. Also 'particular' would be more used if we are talking about identifying somebody or something from others, many times in a negative way, to express that the requirements are not outstanding or different. "We don't have anything planned in particular." "He wasn't looking for a particular Chinese restaurant - any one would do." Positive - "He was looking for a particular box - the box in the picture." 'Particular' here might not mean better - just identifiable from others.