Isopropylation biphenyl

Figure 4 shows TG profiles of the catalysts used in the isopropylation.20,2127 The amount of coke observed at around 600 °C decreased with the dealumination of HM. Volatile organic compounds, which are ascribed to isopropylated biphenyls encapsulated inside the pores, were also found at 300-350 °C for dealuminated HM with the 2/ 120 ratio higher than 70 (see below). These results suggest that most of the volatile compounds were converted to coke... 

Coke deposits were formed from biphenyl over dealuminated HM only in the presence of propylene, although the amount of coke was less.26,27 Coke deposition occurred in a short period after starting the reaction, and by the contact of 4,4 -DIPB with HM even in the absence of propylene.26 These results suggest that the isopropylated biphenyls produce coke by dehydrogenative condensation at their isopropyl groups on acid sites. Propylene oligomers were formed during the reaction 26 They are alternative precursors of deposited coke. 

Four arm star PIB has been prepared by living polymerization with the 3,3f,5,5f-tetra(2-acetoxy-isopropyl)biphenyl (TCumOAc, 18)/BC13 initiating system in dilute solutions in the -35 to -80 °C range [35]. 

Reaction of biphenyl with propylene over H-Y gave a 41% selectivity to 4-isopropyl biphenyl (8) at 76% conversion (Eqn. 22.4). The use of H-L zeolite gave comparable results but with H-M and H-ZSM-5 considerably lower conversions were obtained. When amorphous aluminum silicate was used as the catalyst a product mixture similar to those obtained with the crystalline zeolites was also obtained, suggesting that these reactions may be taking place on the exterior surface of the zeolites and not in the pores or cages. ... 

Yet another interesting conclusion may be derived from the two-liquid adhesion tension data of Bascom and Singleterry [11] which are recorded in Table III. If Equation 17 is applied to each of two different hydrocarbon liquids, the difference between the two solid-liquid interfacial tensions is just the (negative) difference between the respective two-liquid adhesion tensions. Thus, from the values given in Table III, the solid-liquid tension for isopropyl biphenyl is 8 dynes per cm. greater than that for n-decane. This difference is the same for both oolytetra-fluoroethylene and polyethylene. 

C30H34O5 39865-76-4) see Unoprostone isopropyl [3ait-[3aa,4a( ),5p,6aa]]-[l,l -biphenyl]-4-carboxylic acid hexahydro-2-oxo-4-(3-oxo-l-octenyl)-2i/-cyclopen-ta[A]furan-5-yl ester... 

Sugi, Y., Tawada, S., Sugimura, T., Kubota, Y., Hanaoka, T., Matsuzaki, T., Nakajima, K., and Kunimori, K. (1999) Shape-selective isopropylation of biphenyl over H-mordenites Relationships of bulk products and encapsulated products in the pores. Appl Catal A, 189, 251-261. 

DIPT, see Isopropyl ether Dipentyl, see Decane Diphenyl, see Biphenyl 1,1 -Diphenyl, see Biphenyl 4,4 -Diphenylenediamine, see Benzidine p,p -Diphenylenediamine, see Benzidine Diphenylenemethane, see Fluorene o-Diphenylenemethane, see Fluorene Diphenylene oxide, see Dibenzofuran Diphenyl ether, see Phenyl ether s/m-Diphenylhydrazine, see 1,2-Diphenylhydrazine lV,A/ -Diphenylhydrazine, see 1,2-Diphenylhydrazine Diphenylnitrosamine, see IV-Nitrosodiphenylamine Diphenyl-lV-nitrosamine, see IV-Nitrosodiphenylamine A,lV-Diphenylnitrosamine, see IV-Nitrosodiphenylamine A,Al-Diphenyl-lV-nitrosamine, see IV-Nitrosodiphenylamine Diphenyl oxide, see Phenyl ether Diphenyltrichloroethane, see p,p -DDT Diphosphoric acid, tetraethyl ester, see Tetraethyl pyrophosphate... 

A number of substances including ethanol, isopropyl alcohol, polybrominated biphenyls, phenobarbital, and benzo( )pyrene have been shown to synergistically affect carbon tetrachloride toxicity." Alcohol has been a concomitant factor in many of the human cases of poisoning, especially in cases in which severe liver and kidney damage have occurred. Some substances such as chlordecone greatly potentiate the toxicity of carbon tetrachloride at... 

Fig. 2 Effect of Reaction Temperature on Isopropylation Catalyzed by HY Zeolite Reaction conditions HY(5.8) 1 g. Biphenyl 50 mmol, Propene 100 mmol, 4 h.

Table 1 Isopropylation of biphenyl catalysed by typical zeolites°...

Figure 2 The isopropylation of biphenyl over HM(220). Reaction conditions biphenyl, 400 mmol HM(220), 2 g propylene pressure, 0.8 MPa temperature, 250° C...

Figure 5 Effect of the dealumination on the product distribution of encapsulated DIP isomers inside pores and of bulk products in the isopropylation of biphenyl. Reaction conditions are the same as in Figure 3.

Table 2 Isopropylation of biphenyl over highly dealuminated H-mordenitef...

Effect of Propylene Pressure on Selectivity - The partial pressure of propylene is also one of key factors for selective formation of 4,4 -DIPB.22"25 The high partial pressure of propylene effectively enhanced the isopropylation, but the selectivity for 4,4 -DIPB decreased at lower partial pressures over HM(220), as shown in Figure 6.24-25 However, the isomerization of 4-IPBP did not occur at any propylene pressures. Because 3,4 -DIPB is a more thermodynamically stable isomer than 4,4 -DIPB,43 this decrease of the selectivity was ascribed to the isomerization of 4,4 -DIPB to 3,4 -DIPB, not to the lower selectivity to 4,4 -DIPB. Figure 7 shows the effect of propylene pressure on the selectivities for 4,4 -DIPB in bulk and encapsulated products. The selectivity of 4,4 -DIPB inside the pores was almost constant at every pressure. These results indicate that the isomerization does not occur inside the pores but at the external acid sites. The effect of the pressure on the isomerization of 4,4 -DIPB was similar to that on the isopropylation of biphenyl. 4,4 -DIPB itself isomerizes significantly to 3,3 - and 3,4 -DIPB over the catalyst in the absence of propylene. However, no significant isomerization of 4,4 -DIPB occurred in the presence of sufficient propylene pressure. On the other hand, the selectivity of 4,4 -DIPB in encapsulated DIPB isomers was almost constant at any pressure. These differences support the hypothesis that the isomerization of 4,4 -DIPB to 3,4 -DIPB occurs on the external surfaces. The isomerization of 4,4 -DIPB under high pressures is considered to be retarded by the preferential adsorption of propylene on acid... 

Isopropylation over HY, HL and Other Zeolites - The catalysis over HY and HL zeolites is quite different from that over HM. The product distribution over HY and HL resembled that of SA the formation of 4,4 -DIPB was non-regioselective (Table l).18-1 These catalyses are not controlled by the environments of the pores because both zeolites have sufficiently large pores for the transition states form all the IPBP and DIPB isomers. Instead, the product distribution markedly changes by the reaction temperature. At low temperatures, the products are determined by the reactivity at 2- and 4-positions of biphenyl for electrophilic alkylation to yield principally 2- and 4-IPBP for IPBP isomers and... 

DIPB isomers with 2-isopropyl groups. This is due to the higher electron density of the 2- and 4-positions compared to the 3-position. However, the amounts of 3-and 4-IPBP, 3,4 - and 3,3 -DIPB increased with increasing temperature. These isomers may be formed by the isomerization of IPBP and DIPB isomers with 2-isopropyl groups because the former isomers are thermodynamically more stable isomers than the latter. These results show that the isopropylation of biphenyl over HY, HL, and SA is controlled by the reactivity of the reactant molecules at low temperatures, and by the thermodynamic stability of the product molecules at higher temperatures. 

Matsuda and his co-workers examined the isopropylation of biphenyl over H-offretite and SAPO-ll.52 H-Offretite has pore size of 0.67x0.68 nm, but its pores have cages in the channels.30 SAPO-ll has pores of 0.63x0.39 nm.30 H-Offretite was less selective for the formation of 4,4 -DIPB than HM although their catalytic activities were comparable. SAPO-ll exhibited a comparable selectivity for 4,4 -DIPB to HM although catalytic activity was low. The formation of 4,4 -DIPB over these two zeolites was shape-selective compared to the thermodynamically attainable level. 

Alkylation with Other Alkenes over H-Mordenite - The steric restriction of the transition state is essential for high selectivity in the isopropylation of biphenyl. The selectivity should be highly dependent on the size of the alkene. 

Effect of the Dealumination of H-Mordenite - The catalytic activities of the isopropylation of naphthalene are not proportional to the acid density and are not enhanced by the dealumination, as is the case of the isopropylation of biphenyl.18,21 22 Figure 9 shows the yields of products and the distributions of... 

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