3905-64-4Relevant academic research and scientific papers
Enthalpy of Steric Inhibition to Solvation due to tert-Butyl Groups on an Anion Radical
Stevenson, Gerald R.,Kokosinski, Jeanette D.,Chang, Yoh-Tz
, p. 6558 - 6562 (1981)
Electro-spin resonance technique have been utilized to measure the enthalpy of electron transfer from the anion radical of naphthalene (N -. , K + ) to 2-tert-butylnaphthalene (TBN) and from the anion radical of TBN (TBN -. , K + ) to 2,6-di-tert-butylnaphthalene (DTBN) in dimethoxyethane (DME).These endothermic enthalpies of electron transfer were combined with the heat of solvation of the gas-phase anion radical of naphthalene plus the gas-phase potassium cation in DME, the heats of solvation of the neutral hydrocarbons in DME, and the heats of vaporization of the hydrocarbons in a thermochemical cycle to yield the enthalpy of solvation of (DTBN -. ) g + (K + ) g in DME.This enthalpy of solvation is about 17 kcal/mol less exothermic than that for (N -. ) g + (K + ) g and is attributed to the steric inhibition to solvation by the tert-butyl groups on DTBN -. .The enthalpy of solvation of (N -. ) g + (K + ) g (-162 kcal/mol) was determined by combining the enthalpy of the reaction of the DME solvated anion radical with water with a series of well-known constants in a thermochemical cycle.Thus, by utilizing a combination of calorimetric and ESR techniques a complete picture of the thermodynamic parameters controlling the stabilities of the solvated and gas-phase anion radicals of N and DTBN has been generated.
Method for high-selectivity preparation of 2, 6-di-tert-butylnaphthalene through naphthalene alkylation
-
Paragraph 0059; 0060; 0061, (2021/08/11)
The invention discloses a method for high-selectivity preparation of 2, 6-di-tert-butylnaphthalene through naphthalene alkylation. The method comprises the steps of adding naphthalene, an alkylation reagent and a catalyst into an organic solvent, and reacting for 2-12 hours at temperature of 120-240 DEG C under the initial pressure of 0-6 MPa, wherein the catalyst comprises a carrier and metal elements loaded on the carrier, the metal elements are zirconium and other metal elements, and the other metal elements are one or more of tungsten, aluminum, magnesium and cerium. According to the method, the naphthalene conversion rate is high, and the ratio of 2, 6-/2, 7-DTBN in the product is greater than that of most reported data. The method has the characteristics of mild operation conditions and high target product selectivity.
Synthesis and Properties of Perylene-Bridge-Anchor Chromophoric Compounds
Avenoso, Joseph,Doble, Samantha,Fan, Hao,Galoppini, Elena,Gundlach, Lars,Harmer, Ryan,Lloyd, Katherine,Rego, Luis G. C.,Yan, Han
, p. 6330 - 6343 (2020/09/18)
The quest to control chromophore/semiconductor properties to enable new technologies in energy and information science requires detailed understanding of charge carrier dynamics at the atomistic level, which can often be attained through the use of model systems. Perylene-bridge-anchor compounds are successful models for studying fundamental charge transfer processes on TiO2, which remains among the most commonly investigated and technologically important interfaces, mostly because of perylene's advantageous electronic and optical properties. Nonetheless, the ability to fully exploit synthetically the substitution pattern of perylene with linker (= bridge-anchor) units remains little explored. Here we developed 2,5-di-tert-butylperylene (DtBuPe)-bridge-anchor compounds with t-Bu group substituents to prevent π-stacking and one or two linker units in both the peri and ortho positions, by employing a combination of Friedel-Crafts alkylations, bromination, iridium-catalyzed borylation, and palladium-catalyzed cross-coupling reactions. Photophysical characterization and computational analysis by density functional theory (DFT) and time-dependent DFT (TD-DFT) were carried out on four DtBuPe acrylic acid derivatives with a single or a double linker in peri (12b), ortho (15b), peri,peri (18b), and ortho,ortho (21b). The energies of the unoccupied orbitals {LUMO, LUMO + 1, LUMO + 2} are strongly affected by the presence of a π-conjugated linker, resulting in a stabilization of these states and a red shift of their absorption and emission spectra, as well as the loss of vibronic structure in the spectrum of the peri,peri compound, consistent with the strong bonding character of this substitution pattern.
Highly regioselective di-tert-amylation of naphthalene over reusable H-mordenite zeolite
Smith, Keith,Al-Khalaf, Alaa K. H.,El-Hiti, Gamal A.,Pattisson, Samuel
experimental part, p. 1103 - 1110 (2012/06/18)
Highly regioselective di-tert-amylation of naphthalene using different alcohols can be achieved over a H-mordenite (HM) zeolite. For example, the tert-amylation of naphthalene using tert-amyl alcohol in cyclohexane over HM (Si/Al = 10) zeolite has been optimised to give a 70% yield of 2,6-dialkylnaphthalenes, of which 2,6-di-tert-amylnaphthalene was produced in 46% yield along with 2-tert-amyl-6-tert-butylnaphthalene (23%) and 2,6-di-tert-butylnaphthalene (1%). This has been achieved by varying the reaction time, temperature, pressure and amounts of tert-amyl alcohol and zeolite. No 2,7-dialkylnaphthalenes were seen under the conditions tried. The zeolites can be easily regenerated by heating and then reused.
Microwave-assisted regioselective alkylation of naphthalene compounds using alcohols and zeolite catalysts
Yamashita, Hiroshi,Mitsukura, Yumi,Kobashi, Hiroko,Hiroki, Kazuaki,Sugiyama, Jun-ichi,Onishi, Kiyotaka,Sakamoto, Tetsuo
experimental part, p. 145 - 149 (2010/08/20)
Regioselective alkylation of naphthalene compounds with alcohols smoothly proceeded in the presence of zeolite catalysts under microwave irradiation. A H-mordenite (H-M) zeolite catalyst (SiO2/Al2O3 ratio = 240) showed the highest efficiency. In the microwave reactions, high reaction rates and high selectivities for 2,6-dialkylnaphthalenes were achieved. In the best case for the reaction of 2-isopropylnaphthalene with isopropyl alcohol, the conversion and the selectivity were 43.5% and 66.4%, respectively. In di-tert-butylation of naphthalene with tert-butyl alcohol, the conversion and the selectivity reached 86.5% and 70.4%, respectively. The conversions and the selectivities were generally higher than those obtained by conventional oil bath heating.
The alkylation of naphthalene over one-dimensional fourteen-membered ring zeolites. the influence of zeolite structure and alkylating agent on the selectivity for dialkylnaphthalenes
Sugi, Yoshihiro,Maekawa, Hiroyoshi,Naiki, Hiroaki,Komura, Kenichi,Kubota, Yoshihiro
experimental part, p. 1166 - 1174 (2009/05/06)
The alkylation, i.e., isopropylation, s-butylation, and t-butylation, of naphthalene (NP) was examined over one-dimensional fourteen-membered (14-MR) zeolites: CIT-5 (CF1), UTD-1 (DON), and SSZ-53 (SFH), and compared to the results over H-mordenite (MOR)
The alkylation of naphthalene over one-dimensional twelve-membered ring zeolites. the influence of zeolite structure and alkylating agent on the selectivity for dialkylnaphthalenes
Sugi, Yoshihiro,Maekawa, Hiroyoshi,Naiki, Hiroaki,Komura, Kenichi,Kubota, Yoshihiro
supporting information; experimental part, p. 897 - 905 (2009/04/14)
Alkylation, i.e., isopropylation, s-butylation, and t-butylation, of naphthalene (NP) was examined over one-dimensional twelve-membered (12-MR) zeolites: H-mordenite (MOR), SSZ-24 (AFI), SSZ-55 (ATS), and SSZ-42 (IFR) in order to elucidate how zeolite str
A perimidine-derived non-kekule triplet diradical
Quast, Helmut,Nuedling, Wolfgang,Klemm, Gerhard,Kirschfeld, Andreas,Neuhaus, Patrik,Sander, Wolfram,Hrovat, David A.,Borden, Weston Thatcher
, p. 4956 - 4961 (2008/12/20)
(Chemical Equation Presented) 6,9-Di(tert-butyl)-1-methyltetrazolo[1,5-a] perimidine (1) has been synthesized from naphthalene in seven steps. The EPR spectra, recorded after irradiation of 1 in a butyronitrile matrix at 77 K (λ = 351 nm) and in Ar and Xe matrixes at 4.6 K (λ ≥ 345 nm), showed a six-line, high-field signal (Δms = ± 1), centered at 3350 G in butyronitrile, along with a half-field signal (Δms = ± 2), which is characteristic for triplets. Simulation of the observed EPR spectra gave values for the zero-field splitting parameters of |D/hcl/ cm-1 = 0.0105, |E/hcl/cm-1 = 0.0014 in butyronitrile and |D/hcl/cm-1 = 0.0107, |ER/hcl/cm-1 = 0.0016 in Ar. These EPR parameters are consistent with the diradical 5,8-di(tert-butyl)-2-(N-methylimino)perimidine-1,3-diyl (32) as source of the EPR spectra. Linearity of the Curie-Weiss plot and UB3LYP and (14/14)CASPT2 calculations of the singlet-triplet energy difference (ΔEST ≈ 8-10 kcal/mol) indicate that the triplet is the ground state of 2, as predicted for such a nondisjoint diradical.
Equatorial preference in the C-H activation of cycloalkanes: GaCl 3-catalyzed aromatic alkylation reaction
Yonehara, Fumi,Kido, Yoshiyuki,Sugimoto, Hiraku,Morita, Satoshi,Yamaguchi, Masahiko
, p. 6752 - 6759 (2007/10/03)
GaCl3 catalyzes the aromatic alkylation of naphthalene or phenanthrene using cycloalkanes. The C-C bond formation predominantly takes place at the least hindered positions of the substrates, and equatorial isomers regarding the cycloalkane moiety are generally obtained. The reaction of bicyclo[4.4.0]decane and naphthalene occurs at the 2-position of naphthalene and at the 2- or 3-carbons of the cycloalkane, and the products possess a trans configuration at the junctures and an equatorial configuration at the naphthyl groups. Notably, cis-bicyclo[4.4.0]decane turns out to be much more reactive than the trans isomer, and a turnover number "TON" up to 20 based on GaCl3 is attained. 1,2-Dimethylcyclohexane reacts similarly, and the cis isomer is more reactive than the trans isomer. Monoalkylcycloalkanes react at the secondary carbons provided that the alkyl group is smaller than tert-butyl. Adamantanes react at the tertiary 1-position. The alkylation reaction is considered to involve the C-H activation of cycloalkanes with GaCl3 at the tertiary center followed by the migration of carbocations and electrophilic aromatic substitution yielding thermodynamically stable products. The stereochemistry of the reaction reveals that GaCl 3 activates the equatorial tertiary C-H bond rather than the axial tertiary C-H bond.
Study of regioselective dialkylation of napthalene in the presence of reusable zeolite catalysts
Smith, Keith,Roberts, Simon D.,El-Hiti, Gamal A.
, p. 1552 - 1559 (2007/10/03)
Highly regioselective dialkylation of naphthalene using various alkylating agents can be achieved over zeolite catalysts. For example, the tert-butylation of naphthalene (1) using tert-butanol in cyclohexane over a dealuminated H-Mordenite (HM) zeolite has been optimised to give a 60% yield of 2,6-di-tert-butylnaphthalene (3) with a 2,6/2,7 ratio of over 50. This has been achieved by varying the reaction time, temperature, solvent, pressure, amount of tert-butanol, solvent and catalyst, Si/Al ratio of the catalyst, and the mode of addition. The zeolites can be easily regenerated by heating and reused.
