The First Minister met Andrew Owens, the chief executive of London-based Greenergy, to discuss whether his firm could purchase the ailing business from Ineos.
The escalating dispute prompted a twin-track approach from the Scottish and UK governments: management and unions were urged to agree a deal, while a new owner of the facility was also sought.
The Sunday Herald can reveal that on Thursday afternoon, while Finance Secretary John Swinney was at Grangemouth, the First Minister was 14 miles away chairing talks about the plant being bought over. Salmond secretly met Owens at the Houstoun House hotel in Uphall.
Scottish Enterprise chief executive Lena Wilson was also present at the summit.
The Sunday Herald understands the Scottish Government felt it had to prepare for the worst and was deadly serious about exploring all options to save Grangemouth. It was confident a buyer could be found if that had proved necessary. However, the prospect of any sale was mothballed on Friday after Ineos reversed its decision to close the petrochemical facility and restart the oil refinery.
The revelations come after a dramatic week for Scottish industry.
The dispute between Ineos and the trade union Unite led to the Swiss-based company shutting the refinery and demanding staff agree to changes in their terms and conditions.
After the workforce refused, Ineos announced the closure of the petrochemical side of the business and the loss of about 800 jobs.
Greenenergy was founded in 1992 by Owens. It supplies about 13.5 billion litres of petrol, diesel and biofuel, accounting for more than 25% of Britain's road-fuel market. Its customers include forecourts, oil companies, supermarkets and transport operators. Earlier this year, it started to supply 90 Esso dealers covering Scotland, Wales and the north of England.
Described as the UK's third largest private company, it recorded a £14.6bn turnover in 2012/13 and an operating profit of £21.9m. It also has experience of refineries. In 2012, the company was part of a consortium that acquired the Coryton refinery in Essex. It also bought the former Petroplus refinery site at Seal Sands in Teeside.
Last year, Owens said of the problems facing the industry: "Older European refineries - with technology that could be 30-35 years old - typically have higher maintenance costs, higher sustaining capex costs and higher overhead costs than their newer bigger competitors in fast growth countries such as India."
Owens is estimated to have a personal fortune of more than £100m.
A chemical engineering graduate from Cardiff, he lives in the south west of England, enjoys rally driving and owns a powerboat.
Friday's last-minute deal between Ineos and Unite - in which the union agreed to all the company's demands - appears to have stalled the prospect of a sale in the short-term. The Ineos "recovery plan" is based on the firm receiving a £9m grant from the Scottish Government and a £125m loan guarantee facility from the UK Government as well as changed terms and conditions for staff.
Ineos director Declan Sealy said earlier this week: "Like every business, we look at buying and selling assets and businesses all the time.
"Our focus here today is on trying to implement a survival plan that brings a future for Grangemouth."
Salmond also held high-level talks on Thursday with BP, whose Kinneil terminal relies on steam from Grangemouth. The meeting helped pave the way for a deal to be brokered between management and the union.
A spokesman for First Minister Alex Salmond said: "The Scottish Government was very open about the fact that we were talking to a number of interested parties about Grangemouth, developing a substantial alternative if closure proposals were to proceed.
"In the event, plan A of reversing the decision and securing the investment for the long term was successful, thanks to the joint efforts of many stakeholders and therefore plan B has not been required. Obviously we will not discuss the detail of what were commercial discussions."
A Greenergy spokesman said: "We do not comment on private meetings." A Scottish Enterprise spokesman said the Government's statement incorporates its stance.