Coca-cola Co. reported yesterday a 12.1 percent increase in profits and a 15.2 percent gain in sales for 1977 compared with 1976.

The Atlanta-based company said its 1977 earnings rose to $326.22 million ($2.67 a share) from $290.72 million ($2.38), while sales increased to $3.56 billion from $3.09 billion.

For the fourth quarter, profits climbed to $71.32 million (58 cents) from $62.64 million (51 cents). Sales rose to $87997 million from $745.96 million.

Results for both the fourth quarter and full year of 1976 were restated to include the operations of Taylor Wine Co. and to reflect a 2-for-1 stock split which occured in May 1977.

Coca-cola directors also raised the quarterly dividend to 43.5 cents a share from 38.5 cents, payable April 1 to shareholders of record March 16.

In spite of lower chemical and coal earnings, Occidental Petroleum Corp. had higher earnings of $75.6 million in 1977 against $71.7 million a year earlier.

Earnings per share fell to 99 cents from $1.14, however, because there were 10 million more shares outstanding. Revenues fell to $1.153 billion from $1.616 billion. The sales decline was in the oil and gas division, but the profit shrinkage was in coal and chemical. Petroleum profit was up substantially.

Heavy crude oil production from the British waters of the North Sea enabled Occidental to increase its profit for the year to $217.9 million ($2.92 a share) on revenues of $6 billion from $183.7 million ($2.77) in 1976.

The company said it was considering early application of the "successful efforts" accounting standard for oil and gas producing companies proposed by the Financial Accounting Standards Board.

If this rule had been adopted last year, the company said, it would have reduced earnings fro the year by 89 cents a share. The rule ultimately will require Occidental to make such a restatement of 1977 profits, the company said.