V. Fill in the missing words: resemble, aviation gasoline, processes, extraction, new development

1. Recent years have brought … in the use of adsorbents of a very selective nature called molecular sieves.

2. The quality of kerosene is improved by … of aromatic compounds.

3. Absorbtion and stripping are … used to obtain valuable light products.

4. By this method, isopentane of over 90 % purity is produced for ….

5. The principle of vacuum distillation … those of fractional distillation.