Anti-oxidant Additive in Petroleum

The ZDDP sample, ZDDP was provided by Lei Zhou, Institute of Petroleum Refining, Beijing, China  

DTA— 100 mV heating rate, 20 °C min atmosphere, air flow-rate, 45 ml min sample mass, 12.57 mg reference material, empty crucible. 

GC/TCD2—Bridge current, 240 mA cell temperature, 130 °C chromatographic column, Porapak-QS carrier gas, air flow-rate, 25 mimin.  

The first exotherm (205-250 °C) is caused by oxidation of ZDDP after its oxidative induction period, leading to the reaction of intramolecular isomerization. The second exotherm (250-280 °C) is thermal degradation of the ZDDP. A number of products of the thermal degradation at 280 °C can be seen in the gas chromatogram. 

The endothermic peak at 270 °C is followed by a large exothermic peak at 325 °C. The peak intensities of H2S, COS, SO2 and peaks 6 and 7 on the gas chromatogram increase with increasing decomposition temperature. The thiol is unstable at temperatures higher than 280 °C in air. 

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During the last two decades, the DTA-EGD-GC on-line coupled simultaneous apparatus has been applied in the following fields solid catalysts [77-79], anti-oxidation additives in petroleum [80], thermal characteristics of coal [81-83], mineralogy [60, 84-87], organometallic chemistry [88-90], polymer chemistry [91], pharmaceutical chemistry [92], environmental protection chemistry and the thermal behavior of all kinds of chemical compounds [62, 63]. Numerous DTA-EGD-GC curves are shown in Chapter 13. 

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