Can I use a 1031 exchange if i sold a smaller parcel of vacant land and used those funds toward a larger parcel (vacant land)?

if you got hold of the proceeds from the sale and then used them to purchase the other parcel, 1031 is not available. one of the key requirements to use 1031 is that the proceeds from the sale must be held by an independent outside party and then delivered by that party at closing on the purchased property.  there are other rules all of which must be complied with.