# Transforming Petrochemical Processes: Cutting-Edge Advances in Kaolin Catalyst Fabrication
## 7 Kaolin in Petrochemical Catalysis: From Fundamentals to Innovations
### Kaolin-Driven Catalysis in Petrochemical Processes
#### 7.4.1 Fluid Catalytic Cracking (FCC)
The evaluation of FCC catalysts derived from kaolin in conjunction with commercial catalysts in cracking polypropylene loads demonstrated that highly active commercial FCC catalysts were more efficient in producing gaseous products, although they also led to increased aromatic formation [198]. This underscored the importance of catalyst activity in controlling product distribution. Recent developments in synthesizing recrystallized USY/ZSM-5 zeolites from kaolin revealed that combining these zeolites in the same material enhances the effectiveness of ZSM-5 as a propylene booster [199]. This improvement is attributed to the enhanced ability of ZSM-5 to crack larger olefins and suppress hydrogen transfer when synthesized with USY. One year later, a cost-effective kaolin-based catalyst for upgrading waste cooking oil (WCO) into organic liquid products (OLPs) was prepared [200]. The acid-treated kaolin (ATK) catalyst showed a high yield of 74.4% and produced high-quality liquid products with 93.8% oxygen removal and 22.5% aromatic content. In comparison, a commercial petroleum catalyst (CC) achieved 90.8% oxygen removal but had a higher aromatic content of 55.8%. The study found that weak Lewis acids were associated with deoxygenation, Bronstedacids were associated with hydrogen transfer, and the total Bronsted acid amount was associated with cracking capability. CC primarily followed a carbonium ion reaction mechanism, while kaolin-based catalysts adhered to a free radical mechanism. Deoxygenation active sites were identified using CH3 COOH-TPD. Further innovations in catalyst matrix structures included optimizing the in situ synthesis of zeolite Y from commercial kaolin treated with NaOH solution [201]. It was found that calcination at 1000 \({}^{\circ}\)C produced a matrix with enhanced surface area and mesoporousity, leading to improved zeolite Y dispersion and catalytic activity in FCC applications. Additionally, the synthesis of Si-modified pseudo-boehmite@kaolin composites has shown significant improvements in heavy oil catalytic cracking performance [202]. These composites offered a larger surface area, higher pore volume, and better surface acidity than conventional kaolin matrices, resulting in enhanced gasoline and total liquid yields. Additional studies synthesized NaY and Na[B]Y zeolites on alkaline pretreated kaolin microspheres, finding that boron-increased acidity and mesoporousity resulted in more active FCC catalysts [203]. Comparative research on in situ and incorporated FCC catalysts under iron contamination revealed that in situ catalysts maintained higher bottom upgrading and lower dry gas yields, performing better than their incorporated counterparts [204]. The latest research to date in this field reported that optimization of the accessibility of zeolite Y by adjusting crystallization times improved the distribution of zeolite Y in the outer layer of microspheres, which enhanced mass transfer, acid accessibility, and heavy oil cracking performance [205]. In summary, the advancements in FCC catalysts derived from kaolin have led to notable improvements in catalytic performance, including increased yields, enhanced stability, and better product distribution. These developments reflect the ongoing efforts to optimize FCC catalysts for diverse and challenging feedstocks.