# Polymeric and Crystalline Materials for Effective and Sustainable CO\({}_{2}\) Capture
## 3 Petroleum-Based Polymers
### Porous Organic Polymers
Recently, the group of [PERSON] and coworkers proposed an interesting example of a fully conjugated triazine-thiophene porous organic scaffold (Tt-POP-2) [153] (Figure 6). First, the Tt monomer was prepared by a cyclic trimerization of 2-thiophenecarbonitrile. The polymer was then obtained by a Friedel-Craft allylation in the presence of 1,4-bis(bromoethyl)benzene and FeCl\({}_{3}\) as Lewis acid in 1,2-dichloroethane. Different organic linkers were used. A CO\({}_{2}\) uptake capacity of 1.79 mmol g\({}^{-1}\) at 273 K and 1 bar was observed for Tt-POP-2. Similarly, [PERSON] et al. proposed the preparation of covalent triazine frameworks based on fumaronitrile [152]. Starting from fumaronitrile, ZnCl\({}_{2}\) is added, and the mixture is sealed in a quartz ampule. The latter was heated to a temperatures between 350 and 500 \({}^{\circ}\)C for 40 h to complete the preparation of the covalent triazine framework (CTF-FUM) (Figure 6). A maximal CO\({}_{2}\) uptake of 2.55 mmol g\({}^{-1}\) at 298 K was observed. The introduction of an N/O/S-containing building block is an advised approach to improve adsorption capacity and selectivity. Functional groups and aromatic rings such as amines [154], imidazole [155], triazine [156], as well as azo linkages [157], and Troger bases [158] are usually used on the surface of the POP to increase its CO\({}_{2}\) adsorption. [PERSON] et al. reported the preparation of a POP Schiff base based on a benzene-1,3,5-triyltris((9H-carbazol-9-yl) methananone) [159]. To do so, the authors use a synthetic approach involving a Friedel-Crafts reaction with melanin to generate the corresponding TPOP-3 (Figure 7). An adsorption capacity of 4.09 mmol g\({}^{-1}\) at 273 K and 1 bar was reached. [PERSON] and co-workers have reported the preparation of a benzene-ethylamine polymer network (PPN-81) [154] (Figure 7). The latter was prepared in one step from the reaction of 2,4,6-tris(chloromethyl)mestilbene and ethylene diamine. The presence of secondary amines in the structure of the network afforded a CO\({}_{2}\) uptake of 1.92 mmol g\({}^{-1}\) at 295 K at 1 bar. The same group also reported the preparation of polymers based on a methylbenzene precursor [160]. More specifically, 2,4,6-tris(chloromethyl)-mestilbene (TCM) was reacted with ethylene diamine by a nucleophilic substitution reaction affording polymer NUT-1  
Figure 6: Examples of triazine-based polymers [151; 152; 153]. (Figure 7). The latter reached a CO\({}_{2}\) uptake of 1.87 mmol g\({}^{-1}\) at 273 K and 1 bar with enhanced selectivity towards CO\({}_{2}\) (compared to CH\({}_{4}\) and N\({}_{2}\)). Adamantane moiety has also been used in the preparation of nanoporous organic polymers (NOPs) [164]. Using a Friedel-Crafts approach, 1,3,5,7-tetraphenyladamantane was reacted with formaldehyde dimethyl acetal in the presence of FeCl\({}_{3}\) to afford NOP-53 (Figure 7). The latter shows a CO\({}_{2}\) uptake of 2.27 mmol g\({}^{-1}\) at 1 bar and 273 K while also demonstrating a high selectivity toward CO\({}_{2}\) over N\({}_{2}\) and CH\({}_{4}\). By following the same approach, [PERSON] and coworkers reported nanoporous azo polymers based on triptycene for selective CO\({}_{2}\) uptake [163]. Derivative NAP-1 is obtained by direct coupling of the 2,6-diaminotripycene with 5,10,15,20-tetrakis (4-nitrophenyl)-21H,23H-porphine, through the formation of azo-linkage without any metal catalyst (Figure 7). The authors reported a CO\({}_{2}\) uptake of 2.25 mmol g\({}^{-1}\) at 298 K at 1 bar with a good selectivity over N\({}_{2}\). Similarly, [PERSON] et al. proposed the preparation of tunable nanoporous triptycene, carbazole, and ferrocene-based polymers [165]. The polymers (NOP-50x) were prepared by Friedel-Craft alkylation using, for example, carbazole in the presence of dichloroxylene and FeCl\({}_{3}\) as catalyst (Figure 7). A CO\({}_{2}\) uptake up to 4.22 mmol g\({}^{-1}\) was observed at 273 K and 1 bar for carbazole-based NOP. [PERSON] et al.