Abstract
Two kinds of plasticizers were identified in polyvinyl chloride (PVC) films used for food packaging. One of them was diisononyl adipate, and the other was a mixture of di-n-hexyl adipate, n-hexyl-n-octyl adipate, n-hexyl-n-decyl adipate, di-n-octyl adipate, n-octyl-n-decyl adipate, di-n-decyl adipate and acetyl tributyl citrate.
A method for determination of these adipates was developed as follows: adipates extracted from PVC with n-hexane were converted to dimethyl adipate (DMA) by treatment with boron trifluoride methanol complex. After methyl esterification, 10% sodium sulfate solution was added to the reacted solution and the DMA and constituent alcohols formed were extracted with n-hexane and determined by gas chromatography. DMA and constituent alcohols could be analyzed simultaneously on a single column of 15% PEG-1000.
The value of adipates was calculated from that of DMA and alcohols.
The yields of DMA from various adipates were above 90%. The amounts of adipates in PVC films were 12.0-22.0%.
