orthocarbonic ester

例句：

1. 1. The orthocarbonic ester is a key intermediate in the production of polycarbonates.
   正碳酸酯是生产聚碳酸酯的关键中间体。
2. 2.The orthocarbonic ester was used as a solvent in the chemical industry.
   正碳酸酯用作化学工业的溶剂。
3. 3. The orthocarbonic ester was found to have excellent thermal stability and high mechanical strength.
   正碳酸酯被发现具有优异的热稳定性和高强度。