Composite multi-carbon alcohol cosolvent and preparation method thereof

The present invention discloses a composite multi-carbon alcohol cosolvent and a preparation method thereof. The composite multi-carbon alcohol cosolvent adopts offcuts from an ethanol production plant or a winery as raw materials, wherein the offcuts comprise 40-70% of ethanol, 5-15% of propanol and isopropanol, 5-15% of n-butanol, isobutanol and tert butyl alcohol, 1-5% of amyl alcohol, isoamyl alcohol, hexyl alcohol, heptanol, octanol, nonanol, decanol and other liquid multi-carbon alcohols, and 14-40% of water. With performing steps of the raw material pretreatment, pervaporation membrane dehydration, blending and the like, the composite multi-carbon alcohol cosolvent with the water content less than 0.5% is prepared. The composite multi-carbon alcohol cosolvent can be adopted as an alcohol oil cosolvent, and the assistant dissolution effect of the composite multi-carbon alcohol cosolvent is high. The composite multi-carbon alcohol cosolvent provides lower toxicity than the aromatic alcohol oil cosolvent,