Increased barriers for trade will reduce the number of businesses wanting to do business in the region (different rules, regulations,.and red tape)

They would also create their own currency eventually, so that introduces exchange rate problems. A single currency is almost always better for economic cooperation between states as it removes the uncertainty for long term contracts. Like before the Euro if a german company and an italian company wanted to do business they would have to use 2 different currencies, if one country sufferered a banking crisis that would basically screw over the other as their investment would then be worth a lot less. The UK already had their own currency so this part would actually be worse for Quebec.

Lastly there would be brain drain. Now Quebec is the 2nd most prepared province to go off on its own (diversified economy, warm water ports) but its still a bad idea economically. Despite being a net contributer to the EU budget the UK cant make up for the money the EU gave to the UKs poorer regions, or invested in the countries institutions and industries. Its highly likely the same would happen here. And with the xenophobia for non francophones no longer able to be limited to people from outside Canada i suspect a lot of non Quebecois would leave. Skilled labor being so economically valuable this would just do further damage. Much like the UK outside the union it is harder for them to attract skilled labor from the continent and they are actually now in a net loss for skilled workers dispite increasing immigration.

So no… not at all…

Edit: those rules and regulations i mentioned in the first part im sure would include something about mandating French be used (at least at first) for businesses. The global economy is based on the English language. I work, as a Canadian, in Germany for a Germany company, i work in English every day. my German boss went to China on a business trip, they spoke to every professional the met in English. So while many Quebecois might see independence as preserving their language… That will fall away really quick when they realize the economy is more important. Ironically Quebec is probably more insulated from English by being a part of Canada.