1-Butanol is treated with PCC in $\mathrm{CH}{}_2\mathrm{Cl}{}_2$. The main organic product is

PCC is a mild, anhydrous oxidant that stops at the aldehyde stage for a primary alcohol. 1-Butanol therefore gives butanal, $\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{CH}{}_2\mathrm{CHO}$. Butanoic acid would need an aqueous oxidant such as Jones reagent.