Alkenes rhymes with:
amphetamines, argentines, arlene's, balanchine's, bernstein's, bylines, caesareans, calgene's, carotenes, engines', eritreans, evergreens, feldstein's, finkelstein's, gabardines, hammerstein's, josephine's, libertines, limousines, listerines, magazine's, magazines, magazines', mangosteens, newsmagazines, nicotine's, opalines, peregrines, philippines, philippines', philistines, protein's, proteins, quarantines, seventeens, soybeans, springsteen's, submarine's, submarines, tangerines, thirteen's, vitarine's
Alkenes sounds like:
alaskans, alcan's, aligning, aligns, alkanes, alleghenies, allegheny's, allegiance, allegiances, alleging, allgemeines, allison's, allusions