Alex Salmond said he was leaving the SNP conference immediately after his opening remarks to talk to unions and owners Ineos to help resolve the dispute.
He said the Government could not settle the dispute at the facility, which supplies fuel to three-quarters of Scotland's petrol stations, but would be encouraging dialogue.
Mr Salmond said: "What will happen when Grangemouth is closed is we will be importing more petrol.
"You can be sure the flow continues and the Scottish economy continues to function."
He said he was disappointed there had been no effective resolution, and said he was having separate meetings with Unite union leaders and Ineos Management in Edinburgh.
He added: "Government cannot make agreements but can encourage and create conditions where agreements can be found."
He added that statements from the union and Ineos showed both sides wanted a successful Grangemouth plant and believed it had a great future.
The plant has been shut down by the owners, despite cancellation of a planned strike on Sunday over disciplinary proceedings.
The management said plans to shut down the refinery and petrochemical plant which were under way in preparation for the strike could not be reversed.
Ineos wants a guarantee from the union it will not strike this winter over changes to pay, conditions and pensions. The union said that was blackmail.