Probably possible. OTL Southern secessionists had learned from past crises (e.g., having each state secede indepently and then confederate works better than sending delegates to a confederal convention and then have that convention debate secession).
Whether it succeeds depends on how you game it out. If its the same states as in OTL, the South probably achieves independence.
But earlier on, Southerners hadn't developed as much distinct identity and legal and economic justifications for separation. So you might end up with fewer states seceding, which means that the North might win again. Probably no emancipation as a result.
One mechanism for a smaller confederacy--if you get the confederal convention I mentioned earlier, maybe states like Virginia don't even send delegates. And the delegates from some states will be more moderate. They might favor negotiation with the US rather than outright secession. If outvoted by delegates from the more radical states, they and their states may not feel bound by the vote and stay Union.