Unique vapor phase synthesis of 1,2,3,5,6,7-hexahydrodicyclopenta[b,e]pyridine selectively over Co–Al-MCM-41

Methylation of Naphthalene with Methanol over the Al-Modified SiO2 Zeolite Catalysts

“…Figure a shows the NH 3 -TPD curves of the SiO 2 and Al-SiO 2 samples. In general, the weak and strong acid sites are represented by NH 3 desorption peaks in the temperature ranges of 50–200 and 200–550 °C, respectively . In these molecular sieve samples, except 30Al-SiO 2 , the peak temperatures of weak acids are relatively close.…”

“…In general, the weak and strong acid sites are represented by NH 3 desorption peaks in the temperature ranges of 50−200 and 200−550 °C, respectively. 46 In these molecular sieve samples, except 30Al-SiO 2 , the peak temperatures of weak acids are relatively close. However, the peak temperature of 30Al-SiO 2 shifts significantly to the high-temperature region, indicating that the intensity of the acid sites increases.…”

Capturing 1,3-butadiene by the highly ordered Al-containing SBA-15

“…AS10 sample possessed several more desorption peaks: peaks (ii) and (iii) near 410 K and 460 K were assigned to moderate strong Brønsted acid sites [30], the one in 480-550 K originated from strong Brønsted acidic sites owing to the presence of trivalent aluminum in different framework positions [31], and the peak (iv) around 600 K was attributed to Lewis acid sites that might arise from tricoordinated aluminum in framework [32]. With the smaller Al-content, AS80 sample showed the lower desorbed amount of NH 3 than AS10 (Table 1), confirming the relation between the newly formed acidic sites and the Al species incorporated into framework of the composite [33]. On the other hand, the amount of NH 3 -desorbed in the four samples with the same Si/Al ratio of 10 increased in the order of AS10 > 10AS(imp) > 10AS(g-as) > 10AS(g), indicating the high efficiency of one-pot synthesis in creating acidic site on SBA-15.…”

Surface characterization and catalytic evaluation of copper-promoted Al-MCM-41 toward hydroxylation of phenol

“…2 T 2 g transitions of Cu 2+ situated in a more or less tetragonally distorted octahedral environment with a distorted Oh symmetry. Al-MCM-41 shows a low temperature (LT) and a high temperature peak (HT) peak [31]. Similarly we have two distinct desorption peaks in the case of the Cu/Al-MCM-41 sample.…”