## 2 The Precursor (P)MCM-22 and MCM-22 Zeolites
### Structure Directing Agent (SDA)  
The design of SDA for the synthesis of zeolites is a subject of continuous research and, for the MWW topology, it is possible to synthesize different materials with other SDAs than HMI. Here, the use of different SDAs is organized in chronological order. 1987--An aluminosilicate-based material was discovered, named SSZ-25, which exhibited the same characteristics as MWW materials [31]. However, it was initially assumed that the material only had 12-ring channels. Subsequently, it was confirmed that the structure of SSZ-25 was isomorphic to the structure of PSH-3 previously synthesized with HMI three years prior [32]. In this case, _N,N,N_-trimethyl-1-adamantly ammonium hydroxide (TMAda\({}^{+}\)OH\({}^{-}\)) was used as an SDA. 1988--A material called ERB-1 was reported, which was the first LZP where aluminum and boron were tetrahedrally coordinated into the MWW structure and piperidine was used as an SDA, and the use of alkali cations was not necessary [33]. 1998--TMAda\({}^{+}\)OH\({}^{-}\) was also used to obtain ITQ-1, a pure silica zeolite. To obtain this material, mixtures of TMAda\({}^{+}\)OH\({}^{-}\) with HMI had a particular role in the synthesis because TMAda\({}^{+}\)OH\({}^{-}\) allowed the formation of the external 12-ring hemicavities and HMI contributed to the stabilization of the sinusoidal 10-ring channels present in the internal structure of the MWW lamella [14]. 2004--The use of diethyldimethylammonium (DEDMA), ethyltrimethylammonium (ETMA), or hexamethonium (HM) cations as the SDA were reported, and the obtained material was called UZM-8 [34]. UZM-8 was synthesized with a Si/Al molar ratio between 6.5 and 35 and a disordered lamellar structure similar to that of MCM-56 zeolite. 2006--The use of _N_-methylsparteinium (MSPT) as an SDA in a high-throughput synthesis led to the discovery of ITQ-30, an MWW-type zeolite with disordered lamellae similar to MCM-56 [35]. 2011--The use of (bis(\(N\),\(N\),\(N\)-trimethyl)-1,5-pentanediaminium dibromide as an SDA was reported and conducted to form an EMM-10 precursor [36]. The material is similar to (P)MCM-22, but its lamellae are vertically misaligned. 2013--The use of 1,3-diisopropylimidazolium, a 1,3-diisobutylimidazolium cation, and 1,3-dicyclohexylimidazolium cations were reported to obtain a zeolite named SSZ-70 [37]. 2015--A new synthesis of MWW-type materials was reported. It employed 1,3-bis (cyclohexaryl)imidazolium hydroxide (IM\({}^{+}\)OH\({}^{-}\)) as an SDA, and the obtained materials were called ECNU-5A and ECNU-5B [38]. The procedure used calcined ITQ-1 as a silica source, which was recrystallized with an aqueous solution containing IM\({}^{+}\)OH\({}^{-}\). The crystals of MWW rapidly dissolved due to the high basic pH in only 1 h at 170 \({}^{\circ}\)C, yielding only 17.8% and increasing to 92.3% after 24 h. The obtained materials showed a horizontal displacement with misaligned MWW lamellae structure in ABAB or ABC stacking sequence, caused by the geometry between IM\({}^{+}\)OH\({}^{-}\) and the silica structure. The use of aniline (AN) with mixtures of HMI for the synthesis of MWW zeolites was reported [39; 40]. In this case, AN acts as a structure-promoting agent via space filling, and the authors pointed out that the use of AN contributed to the formation of the zeolitic structure because the molecules were not trapped within the MWW structure. Moreover, its recovery and recycling may contribute to low-cost synthesis. 2017--1-adamantanamine as an SDA was reported and the obtained material, called ECNU-10, had a three-dimensional structure analogous to MCM-49 zeolite [41]. ECNU-10 could be obtained when the gel Si/Al ratio was 12-13.5 in a relatively narrow phase region. 2018--A direct synthesis of three-tridimensional MCM-49 using cyclohexylamine (CHA) as an SDA was reported [42].