Isopropylation naphthalene

Contrary to molecular sieving, spatioselectivity does not depend on the relative rates of diffusion and reaction, hence both can be easily distinguished changing the crystallite size has no effect on spatioselectivity whereas it increases selectivity by molecular sieving. However, the two types of selectivity may act simultaneously as was shown by Song et al. (42) for naphthalene isopropylation over H-mordenite. 

In naphthalene isopropylation, 2,6-diisopropylnaphthalene selectivity is much higher over dealuminated mordenite than over HY, HL, or other large pore zeolites. [73-75]. 

Sugi and coworkers have reported detailed results on the effect of Si02/Al203 ratio of mordenite on naphthalene isopropylation with propylene [Kim et al., 1995a]. They analyzed not only the bulk of the reaction products, but also the products trapped in the pores of mordenite after the isopropylation. The results reveal that inside the mordenite pore channel 2,6-diisopropylnaphthalene was formed in a much higher selectivity than 2,7-diisopropylnaphthalene, but the external surface sites contribute more to the non-selective reactions as well as coke formation. The same group also reported that the impregnation of cerium is an effective method for... 

Analytical grade cyclohexane, naphthalene, isopropyl bromide, cyclohexyl bromide and cyclohexene (Aldrich Company) were used without further purification. 

Nanocrystals, anatase Nanocrystals, offretite Nanoemulsion template Nanoparticles agglomerates, MFI Nanoparticles, Au Nanoparticles, Fe203 in MCM-41 Nanoparticles, Sn02 Nanoparticles, surfactant stabilized Nanoparticles, Zr02 in SBA-15 Nanoscopic precursor particles Nanoslabs, silicalite-1 Nanowires in FSM-16 Nanowires, Se in MFI Naphtha isomerisation Naphthalene isopropylation Naphthalene alkylation 25-0-03 25-P-Naphthene ring opening S-Naproxen synthesis... 

C-Alkylations may be discussed under the headings of alkene reactions and A/-alkyl rearrangements. The isopropylation of benzene and naphthalene are two important examples of alkylation with alkenes (see Alkylation). Manufacture of j butylaniline, by heating /V-butylaniline with 2inc chloride, typifies the rearrangement reaction appropriate to and higher alkyl derivatives. 

This type of polarization appears to be general in such systems and it has been proposed that it arises because of T i-S mixing. An interesting and important addif ional observation comes from a study of the reaction of isopropyl chloride with sodium naphthalene in a field of 60 G. Net emission in the products is predicted for T i-S mixing and multiplet polarization for Tq-S mixing. Since no multiplet polarization can be detected, it would seem that Tq-S mixing is suppressed in this system (Garst et al., 1971). Presumably, the naphthalene radical anion... 

The cycloadducts 25 and 26 have unique structures. Two isopropyl groups on the cyclotetrasilane ring are located over the benzene ring or the naphthalene ring. The short distances between the methine protons of the two isopropyl groups and the aromatic rings (25 2.81 and 2.86 A, 26 2.49 and 2.61 A) cause an upheld shift of the lH NMR signals of the methine protons (25 8 0.18 ppm, 26 8 —0.17 ppm) (Scheme 17). 

Kureha A process for making di-isopropyl naphthalene mixtures from naphthalene and propylene by transalkylation. It operates at 200°C, using a silica/alumina catalyst. Operated in 1988 at the Rutgerswerke plant in Duisberg-Meiderich, Germany. The name has also been used for a process for making acetylene from petroleum. 

The above example clearly points to nonenzymatic hydrolysis of 3,4-dimethyl-5-phenyloxazolidine (11.106). However, enzymatic hydrolysis cannot entirely be ruled out. A related compound, 3-isopropyl-5- [(naphthalen-... 

Bromonaphthalene has been reduced to naphthalene in good yield by hydrogenation over Raney nickel in methanolic potassium hydroxide, by triphenyltin hydride in benzene, by magnesium in isopropyl alcohol, by sodium hydrazide and hydrazine in ether, and by copper(I) acetate in pyridine. ... 

MMUS Naphthalene,1,2,3,4-tetrahydro-7-isopropyl-1,1,2,4, 4-pen tamethyl-6,8-dinitro... 

Some data for the alkylation of naphthalene by isopropyl bromide under various conditions are given. 

Table IV summarizes the pertinent characteristics of some of the naphthyl carbonyl compounds. All of these compounds emit from a it,7T triplet very similar to that of naphthalene. Those that have been studied are resistant to photoreduction in isopropyl alcohol and photocycloaddition with 2-methyl-2-butene25 and isobutylene.17 Significant oxetane formation was, however, observed with the aldehydes, albeit with only moderate efficiency (quantum yield approximately one-tenth that of benzaldehyde).25...

A] is the concentration of acceptor and [CH2] is the solvent concentration. The ke to ku ratio has been measured for benzophenone in isopropyl alcohol, the most commonly used system for sensitized photoreductions. From a study of naphthalene quenching of benzophenone photoreduction, Beckett and Porter107 found that ke = 192fcH[CH2]. 

Cadinene is a trivial name of a number of isomers which occur in a wide variety of essential oils e.g. cubeb oil. Actually, it is derived from the Cade juniper Juniperus oxycedrus L.). The cadalane (4-isopropyl-1,6-dimethyldecahydro-naphthalene) carbon skeleton is the base. Prominent stereochemical isomers are a-cadinene 79, y-cadinene 80 and d-cadinene 81 (Structure 4.23). This group is also known as naphthalene-type sesquiterpenes. 

Sugi and his co-workers found that ceria modification of HM effectively deactivated the external acid sites in the isopropylation of biphenyl49 and naphthalene,50,51 as will be discussed in the section 4.2.3. 

Catalysis over Typical Zeolites - In the alkylation of naphthalene, a-alkylation occurs in the initial stage because -positions are more reactive than P-positions. However, the (3/a ratio in the product mixture increases with the increase of reaction temperature and time on stream. Figure 8 shows the three reaction paths for producing diisopropylnaphthalene (DIPN) isomers. The reactions are (1) alkylation, (2) isomerization, and (3) transalkylation. Isomerization and transalkylation accompany the rearrangement of isopropyl groups. The zeolite type and reaction conditions, e.g., temperature and time on stream, usually determine the type of reaction path.4... 

Table 4 Isopropylation of naphthalene over typical zeolite...

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... 

Figure 9 Effect of the dealumination of HM on the isopropylation of naphthalene. Reaction conditions naphthalene, 400 mmol HM, 5 g propylene pressure, 0.8 MPa temperature, 250 °C.

---