Polystyrene is used in a wide range of applications in our lives, from machine housings to plastic cups and miniature electronic devices. When polystyrene is used, a large amount of waste is produced, which can cause pollution to the environment and even harm biological and human health. Due to its low bulk density (especially the foamed type) and low residual value, polystyrene cannot be easily recycled. Often waste polystyrene is difficult to recycle. In this paper, waste polystyrene has been modified by using acetic anhydride which caused a crude oil flow improver. The results showed that modified polystyrene improves the flow properties of the crude oil, reducing the viscosity and the pour point of the crude oil by up to 84.6% and 8.8 °C, respectively. Based on the study of the paraffin crystal morphology, the mechanism of improving the flow capacity of crude oil by modified polystyrene was proposed and analyzed.

The quantitative structure–property relationship (QSPR) models for predicting the octane number (ON) of toluene primary reference fuel (TPRF; blends of n-heptane, isooctane, and toluene) was investigated. The electrotopological state (E-state) index of TPRF components was computed and weight-summed to generate the quantitative descriptor of TPRF samples. The partial least squares (PLS) technique was used to build up the regression model between the ON and weight-summed E-state index of the investigated samples. The QSPR models for the research octane number (RON) and motor octane number (MON) of TPRF were built. The prediction performance of the obtained PLS models was assessed by the external test set validation and leave-one-out cross-validation. The validation results demonstrate that the proposed PLS models are feasible for predicting the ON, both RON and MON, of TPRF. In addition, several other QSPR models for the ON of TPRF were developed by employing the stepwise regression and Scheffé polynomials methods, and the prediction performance of these models were compared with that of the PLS models. The comparison result shows that the proposed PLS models are slightly better than multiple linear regression models and Scheffé models. It is demonstrated that the combination of the E-state index and PLS is an easy-to-use and promising method for studying and forecasting the ON of TPRF.

In order to further improve the comprehensive experimental skills of applied chemistry undergraduates, a comprehensive experiment of crude oil viscosity, yield value, viscosity temperature curve and viscosity reducer evaluation was designed. Through the determination of different physical parameters of crude oil and the evaluation of viscosity reducer, the characteristics of crude oil and the effect of viscosity reducer are comprehensively evaluated. The design of the experiment has significant pertinence and applicability, effectively deepening students' understanding of some physical properties of crude oil, and further improving students' experimental operation ability, experimental observation ability and problem solving skills. At the same time, the determination of some physical parameters of crude oil makes students realize that physical parameters are indispensable for guiding further development work in the oil fields and gas fields, and at the same time deepen the study of the principle of measuring some physical parameters.

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