(Adds stocks)

Shares in PTT Global Chemical Pcl gained 1.54 percent to 65.75 baht, after hitting a high of 66 baht at one point, while brokers remained positive on its earnings outlook despite concerns over weaker oil prices.

PTT Global Chemical's first quarter net profit jumped 143 percent from last quarter to 9.85 billion baht ($316.52 million), in line with market expectation.

"Despite weaker oil prices prompting concerns over second quarter earnings, we still expect that the prices won't slump too severely. In the mid-term, the oil price decline will help boost the company's refinery business and aromatics," Broker Maybank Kim Eng said in a research note.

"Furthermore, PTT Global Chemical operates on low production cost, giving it an advantage among its peers," the broker said.

Maybank gave the shares a buy rating with target price at 78 baht.

Several brokers expect the petrochemical industry to continuously improve in the last half of this year until 2013.

1118 (0418 GMT)

(Reporting by Sinsiri Tiwutanond in Bangkok; sinsiri.tiwutanond@thomsonreuters.com)