# Utilization of Polymeric Materials toward Sustainable Biodiesel Industry: A Recent Review
## 3 Polymeric Catalysts
### Chemically Synthesized Polymeric Catalysts  
Chemosynthetic polymeric catalysts are commercialized polymeric chemicals synthesized in the lab based on specific parameters and conditions to catalyze triglycerides trans  
Figure 4: Esterification/Transesterification reactions to produce biodiesel fuel. esterification and FFA esterification. There is a wide range of chemosynthetic polymeric catalysts that include acidic, basic, organic, inorganic, and hybrids of organic-inorganic, porous, and metals. FDU-15-SO\({}_{3}\)H is an example of acidic organic pours polymeric catalysts. H\({}_{2}\)SO\({}_{4}\) was the agent to sulfonate FDU-15 polymer. This polymeric composite with large surface area 447 m\({}^{2}\)/g proves efficiency to convert 99% of soybean oil into FAME in the first run and 90% in the fourth cycle [63]. Polymeric ionic liquids were introduced as an ecofriendly catalysis approach in a variety of industrial chemistry including biofuel production. Poly divinylbenzene (PDVB-IL) is an ionic liquid catalyst synthesized through copolymerizing acidic ILs oligomers and DVB. The conversion efficiency for PDVB-IL was 99% and the reusability efficiency was 89% in the sixth cycle [64]. Moving to basic catalysts, resin-N\({}_{3}\)=P(MeNCH\({}_{2}\)-CH\({}_{2}\))\({}_{3}\)N was synthesized by [PERSON] et al. [65]. The more interesting thing about this polymeric basic catalyst is the highest efficiency, which reached 100% to convert soybean oil into biodiesel within 3 h at room temperature, 25 \({}^{\circ}\)C. Another unique polymeric catalyst is poly (butanesulfonic acid pyrrole) coated magnetic iron oxide. It was synthesized by a hybrid mixture of organic/inorganic chemicals. The most important feature of this hybrid polymeric catalyst is the rate of reusability which reached 97.5% in the tenth cycle [66]. Metal-organic frameworks were modified to synthesize MIL-100(Fe)@DAILs catalyst. It was synthesized by encapsulating dicationic acid into MIL-100(Fe) framework [67]. The redox property of polyoxometalates was utilized to synthesize acidic heterogeneous catalyst HPW@MIL-100(Fe) which proves 96.3% efficiency to esterify FFA into FAME with reusability capability 95.5% in the fifth cycle [68]. Moreover, the alkalinity property of some metal-organic frameworks was utilized to prepare an alkaline polymeric acid Fe\({}_{3}\)O\({}_{4}\)@HKUST-1-ABILs that can trans-esterify 92.3% of soybean oil into biodiesel fuel [69]. 90% of oleic acid can be esterified by HZnPS-1 catalyst which was synthesized by optimizing the chemical reaction of p-xylenediphosphonic acid and anhydrous ZnCl\({}_{2}\) and sulfonating the obtained resultants [70]. Oligocat was the given name for the novel catalyst synthesized by [PERSON] et al. [9; 10]. It behaves as a pseudo-homogeneous acidic catalyst, demonstrating 96.5% conversion efficiency even after the third cycle. Lastly, Pd/HPS catalytic polymeric material was prepared by immobilizing palladium nanoparticles into hyper-crosslinked polystyrene. These kinds of polymer-metal catalysts were used to catalyze the hydrodeoxygation reaction, which is a new approach to produce hydrocarbon-based biodiesel. [PERSON] et al. [71] used Pd/HPS to catalyze the hydrodeoxygation reaction of stearic acid which led to 97% conversion into n-heptadecane. Table 4 explores the conversion and reusability efficiencies of some chemically synthesized polymeric catalysts.