138-86-3Relevant articles and documents
Generation of Br?nsted acid sites on Al2O 3-supported Ta2O5 calcined at high temperatures
Kitano, Tomoyuki,Okazaki, Shota,Shishido, Tetsuya,Teramura, Kentaro,Tanaka, Tsunehiro
, p. 189 - 196 (2012)
An alumina-supported tantalum oxide (Ta2O5/Al 2O3) calcined at 1223 K promoted both Friedel-Crafts alkylation of anisole with benzyl alcohol and isomerization of α-pinene, and exhibited Bronsted acidity despite the high temperature calcination. Among the Ta2O5/Al2O3 catalysts tested, 33 wt% Ta2O5/Al2O3 calcined at 1223 K showed the highest activity. A monolayer of tantalum acid-like compound, which has distorted octahedral symmetry, was stabilized over 33 wt% Ta 2O5/Al2O3 catalyst calcined at 1223 K. The two-dimensional Ta-O-Ta network of stabilized tantalum acid-like compound probably accounts for the generation of Bronsted acid.
Isomerization of α-Pinene over Immobilized AlCl3 Catalysts
Wu, Yihui,Tian, Fuping,He, Min,Cai, Tianxi
, p. 1138 - 1142 (2011)
Immobilized AlCl3 catalysts supported on γ-Al2O3 and SiO2 were prepared by a two-step vapor method and their catalytic activities were evaluated by the liquid phase isomerization of α-pinene for the first time. The results showed that the immobilized AlCl3 catalyst gave excellent catalytic performance for the isomerization of α-pinene. The AlCl3/SiO2 catalyst gave 98.4% conversion of α-pinene and 93.7% selectivity for the main products such as camphene, limonene, and terpinolene at a reaction temperature of 40 °C. The AlCl3/γ-Al2O3 catalyst gave much higher activity, 95.5% conversion of α-pinene and 94.4% selectivity for the main products even at temperatures as low as 30 °C. The excellent catalytic performance of the immobilized AlCl3 catalysts is due to their strong acidity.
-
Huchette et al.
, p. 1035 (1979)
-
Superacidity in sulfated metal-organic framework-808
Jiang, Juncong,Gándara, Felipe,Zhang, Yue-Biao,Na, Kyungsu,Yaghi, Omar M.,Klemperer, Walter G.
, p. 12844 - 12847 (2014)
Superacids, defined as acids with a Hammett acidity function H0 ≤ -12, are useful materials, but a need exists for new, designable solid state systems. Here, we report superacidity in a sulfated metal-organic framework (MOF) obtained by treating the microcrystalline form of MOF-808 [MOF-808-P: Zr6O5(OH)3- (BTC)2(HCOO)5(H2O)2, BTC = 1,3,5-benzenetricarboxylate] with aqueous sulfuric acid to generate its sulfated analogue, MOF-808-2.5SO4 [Zr6O5(OH)3(BTC)2- (SO4)2.5(H2O)2.5]. This material has a Hammett acidity function H0 ≤ -14.5 and is thus identified as a superacid, providing the first evidence for superacidity in MOFs. The superacidity is attributed to the presence of zirconiumbound sulfate groups structurally characterized using single-crystal X-ray diffraction analysis.
Gas-Phase Pyrolysis of Isotopically and Stereochemically Labeled α-Pirene: Evidence for a Nonrandomized Intermediate
Gajewski, Joseph J.,Hawkins, Christopher M.
, p. 838 - 839 (1986)
-
Thermolysis of α-pinene in supercritical lower alcohols
Chibiryaev,Anikeev,Yermakova,Mikenin,Kozhevnikov,Sal'nikova
, p. 987 - 992 (2006)
Thermal isomerization of α-pinene in supercritical solvents, viz., ethanol, methanol, and propan-1-ol, was carried out, and differences in the rate and selectivity of the process were revealed. In supercritical ethanol the reaction rate increases sharply and the selectivity remains unchanged with an increase in the temperature (from 290 to 390°C) or pressure (from 90 to 270 atm). The main reaction products are limonene, isomeric alloocimenes, and pyronenes. The selectivity for limonene in propan-1-ol is higher than in other alcohols when the conversion of α-pinene not higher than 50%. In supercritical ethanol (430°C, 120 atm, 140 s) limonene is more stable than α-pinene (conversion 8%).
Biochemistry and molecular genetics of the biosynthesis of the earthy odorant methylisoborneol in Streptomyces coelicolor
Wang, Chieh-Mei,Cane, David E.
, p. 8908 - 8909 (2008)
Methylisoborneol (2) is a volatile organic compound produced by a wide variety of Actinomycete soil organisms, myxobacteria, and cyanobacteria. It has an unusually low odor threshold and, together with geosmin, is responsible for the characteristic smell of moist soil as well as unpleasant taste and odor episodes associated with public water supplies and contamination of various foodstuffs, including fish, wine, and beer. Despite considerable interest in detection and remediation of methylisoborneol, the biosynthesis of this methylated monoterpene has been obscure. In Streptomyces coelicolor, the sco7700 and sco7701 genes are shown to correspond to a two-gene operon responsible for methylisoborneol biosynthesis. Both genes have been amplified by PCR and the resulting DNA has been cloned and expressed in Escherichia coli. Incubation of recombinant SCO7701 protein, annotated as a possible C-methyltransferase, with geranyl diphosphate (1) and S-adenosylmethionine gave the previously unknown compound, (E)-2-methylgeranyl diphosphate (3). Incubation of 3 in the presence of Mg2+ with recombinant SCO7700, previously annotated only as a possible metal-binding protein or terpenoid synthase, resulted in the formation of 2-methylisoborneol (2). The steady-state kinetic parameters for both biochemical reactions have been determined. Incubation of geranyl diphosphate and S-adenosylmethionine with a mixture of both SCO7700 and SCO7701 resulted in formation of methylisoborneol (2). Cyclization of 2-methylgeranyl diphosphate (3) to methylisoborneol (2) likely involves the intermediacy of 2-methyllinalyl diphosphate. Copyright
Monoterpenes etherification reactions with alkyl alcohols over cesium partially exchanged Keggin heteropoly salts: effects of catalyst composition
da Silva, Márcio José,Lopes, Neide Paloma Goncalves,Ferreira, Sukarno Olavo,da Silva, Rene Chagas,Natalino, Ricardo,Chaves, Diego Morais,Texeira, Milena Galdino
, p. 153 - 168 (2021)
In this work, cesium partially exchanged Keggin heteropolyacid (HPA) salts were prepared, characterized, and evaluated as solid catalysts in monoterpenes etherification reactions with alkyl alcohols. A comparison of the activity of soluble HPAs and their insoluble cesium salts showed that among three different Keggin anions the phosphotungstate was the most efficient catalyst. Assessments on the effects of the level of the protons exchange by cesium cations demonstrated that Cs2.5H0.5PW12O40 solid salt was the most active and selective phosphotungstate catalyst, converting β-pinene to α-terpinyl methyl ether. The influences of the main reaction parameters such as reaction temperature, time, catalyst load, substrate nature (i.e., alcohols and monoterpenes) were investigated. We have demonstrated that the simultaneous presence of the cesium ions and protons in the catalyst plays an essential role, being the 2.5–0.5 the optimum molar ratio. The Cs2.5H0.5PW12O40 salt was efficiently recovered and reused without loss of catalytic activity. Graphic abstract: [Figure not available: see fulltext.]
-
Conant,Carlson
, p. 3464 (1929)
-
-
von Rudloff
, p. 1 (1961)
-
Winogradowa
, (1931)
Synthesis of mesoporous Beta and Sn-Beta zeolites and their catalytic performances
Jin, Junjiang,Ye, Xinxin,Li, Yongsheng,Wang, Yanqin,Li, Liang,Gu, Jinlou,Zhao, Wenru,Shi, Jianlin
, p. 8196 - 8204 (2014)
Mesoporous Beta zeolite has been successfully prepared through hydrothermal synthesis in the presence of cationic ammonium-modified chitosan as the meso-template. Through a subsequent solid-gas reaction between highly dealuminated mesoporous Beta zeolite and SnCl4 steam at an elevated temperature, mesoporous Sn-Beta has been facilely obtained. It was revealed that the addition of cationic chitosan induced the nanocrystal aggregation to particle sizes of ～300 nm, giving rise to the intercrystalline/interparticle mesoporosity. In the Sn-implanting procedure, Sn species were demonstrated to be doped into the framework of the resulting mesoporous Beta zeolite in a tetrahedral environment without structural collapse. Due to the micro/mesoporous structures, both mesoporous Beta and Sn-Beta exhibited superior performances in α-pinene isomerization, Baeyer-Villiger oxidation of 2-adamantanone by hydrogen peroxide and the isomerization of glucose in water, respectively. the Partner Organisations 2014.
Synthesis of terpinyl acetate using octadecylamine ethoxylate ionic liquids as catalysts
Li, Lu,Liu, Shiwei,Shi, Yanjing,Yu, Shitao,Xie, Congxia,Qi, Chunjie
, p. 2095 - 2105 (2013)
Terpinyl acetate, an important natural flavor, can be synthesized by esterification of α-pinene with acetic acid under acidic conditions. In this work, seven acidic ionic liquids were first synthesized, using octadecylamine ethoxylates (AC 1810, AC 1815, AC 1820, and AC 1830) as the cations, and characterized by FT-IR, 1H NMR, and 13C NMR spectroscopy. The ionic liquids were then used as catalysts in the synthesis of terpinyl acetate. The effect of preparation conditions on catalyst performance was examined. It was found that the acidic ionic liquid 1-(3-sulfonic acid)propyl-3-poly(ethylene glycol) octadecylamine polyoxyethylene ether tetrafluoroborate ([PAC1815]+[BF4]-) was an excellent catalyst for synthesis of terpinyl acetate. The effects of the conditions used for preparation of terpinyl acetate were examined in detail, and the optimum preparation conditions were obtained. Under the optimum conditions, the yield of terpinyl acetate reached 35.70 %. When the catalyst was reused for the 5th time, the yield of terpinyl acetate was still 32.00 %. The results showed that effective separation and recycling of catalyst could contribute to developing a new strategy for synthesis of terpinyl acetate.
Fuguitt,Hawkins
, p. 242,243 (1945)
The kinetics, stereochemistry, and deuterium isotope effects in the α-pinene pyrolysis. Evidence for incursion of multiple conformations of a diradical
Gajewski, Joseph J,Kuchuk, Ilya,Hawkins, Christopher,Stine, Robert
, p. 6943 - 6950 (2002)
Pyrolysis of optically active α-pinene gave 95% racemic limonene (dipentene), alloocimine, racemic α-pinene, α-pyronene. Activation parameters are reported. Pyrolysis of (S) syn-6-trideuteriomethyl α-pinene at 256.7°C for 2400s gave dipentene with twice as much deuterium as hydrogen transfer with kH/kD=1.49 and alloocimine with a Z and E trideuteriomethyl ratio of ca. 5 with kH/kD=0.89. The isotope effect on loss of starting material was 1.16. Separation of the enantiomers of α-pinene from 3600s pyrolyses at 256.7°C followed by NMR analysis revealed that the ratio of the R-syn to R-anti to S-anti isomers is 4.6:3.7:1 at roughly two half-lives. Kinetic analysis reveals that the previously proposed mechanism for all conversions involving slow interconversion of two diradicals with Cs symmetry is not consistent with the distribution of the ??-pinene isomers, particularly the formation of more suprafacial-retention product (R-anti) than bond-rotated isomer (S-anti). Inclusion of another Cs species (ignoring the deuteriums) that would be intermediate between the originally proposed Cs species, appears more consistent with the observations.
The thermal isomerization of terpene compounds in supercritical alcohols
Anikeev,Ermakova,Chibiryaev,Kozhevnikov,Mikenin
, p. 711 - 716 (2007)
The experimental data obtained were used to construct a kinetic model of the isomerization of α-pinene in supercritical ethanol. The model took into account the influence of both temperature and pressure on the rate and selectivity of the reaction. Nauka/Interperiodica 2007.
Isomerization of α-pinene to camphene
Findik,Guenduez
, p. 1145 - 1151 (1997)
The catalytic isomerization reaction of α-pinene to camphene over a clinoptilolite catalyst was investigated in a batch reactor open to the atmosphere between 130 and 155°C. The catalyst was selective to the isomerization of α-pinene to camphene. The effects of several variables, such as reaction temperature, amount of catalyst, stirring speed and catalyst particle size, on the conversion of α-pinene and selectivity to camphene were determined. The reaction fits a first-order parallel reaction with rate constants of k1 = 3.020·10-2 e-33381.6/RT for the production of camphene and of k2 = 1.576·10-2 e-31096.53/RT for the production of limonene.
A cDNA clone for β-caryophyllene synthase from Artemisia annua
Cai, Yu,Jia, Jun-Wei,Crock, John,Lin, Zhi-Xin,Chen, Xiao-Ya,Croteau, Rodney
, p. 523 - 529 (2002)
An homology-based cloning strategy yielded a full-length cDNA from Artemisia annua that encoded a protein of 60.3 kDa which resembled a sesquiterpene synthase in sequence. Heterologous expression of the gene in Escherichia coli provided a soluble recombinant enzyme capable of catalyzing the divalent metal ion-dependent conversion of farnesyl diphosphate to β-caryophyllene, a sesquiterpene olefin found in the essential oil of A. annua. In reaction parameters and kinetic properties, β-caryophyllene synthase resembles other sesquiterpene synthases of angiosperms. The β-caryophyllene synthase gene is expressed in most plant tissues during early development, and is induced in mature tissue in response to fungal elicitor thus suggesting a role for β-caryophyllene in plant defense.
The influence of water on the isomerization of α-pinene in a supercritical aqueous-alcoholic solvent
Ermakova,Chibiryaev,Mikenin,Sal'nikova,Anikeev
, p. 62 - 67 (2008)
The influence of water as a cosolvent and catalyst of the isomerization of α-pinene in a supercritical aqueous-alcoholic (ethanol) solvent was studied experimentally. At T = 657 K and p = 230 atm, an increase in the concentration of water in the reaction mixture was found to increase the rate of the reaction and its selectivity with respect to the desired product, limonene. Water exhibited the properties of an acid catalyst because of its ionization. Mathematical experimental data processing was performed to evaluate and separate the contributions of the radical and ionic paths to the total rate of the reactions that occurred during the thermal isomerization of α-pinene.
-
Heggie,W.,Sutherland,J.K.
, p. 957 - 958 (1972)
-
-
Nasarow et al.
, p. 320,324; engl. Ausg. S. 303, 306 (1955)
-
Production of p-cymene and hydrogen from a bio-renewable feedstock-1,8-cineole (eucalyptus oil)
Leita, Benjamin A.,Warden, Andrew C.,Burke, Nick,O'Shea, Mike S.,Trimm, David
, p. 70 - 76 (2010)
The catalytic transformation of pure 1,8-cineole was performed in a custom-built down-flow fixed bed pyrolysis rig over various metal-doped alumina pellets controlled at temperatures between 523 K (250 °C) and 873 K (500 °C). Varying amounts of oxygen were added to the feed. Hydrophilic, hydrophobic and gaseous products were analysed separately. The hydrophilic phase was predominantly water, while the composition of the hydrophobic phase varied with catalyst type and contained mainly mixtures of both aromatic and non-aromatic C10 hydrocarbons. The main gases produced were hydrogen, carbon monoxide and carbon dioxide. As the reaction temperature increased, yields of gas phase components increased for all catalysts. The palladium-doped γ-Al2O3 catalyst at ～250 °C showed excellent yields and selectivity for the continuous production of p-cymene together with hydrogen gas. For the best catalysts and reaction conditions, the process is very atom and carbon efficient, with all ten carbon atoms from the cineole molecule being used in the p-cymene product in an oxygen-free environment. The process uses no solvents and the high yields achieved ensure there is no waste clean-up required.
Discovering Monoterpene Catalysis Inside Nanocapsules with Multiscale Modeling and Experiments
Pahima, Efrat,Zhang, Qi,Tiefenbacher, Konrad,Major, Dan T.
, p. 6234 - 6246 (2019)
Large-scale production of natural products, such as terpenes, presents a significant scientific and technological challenge. One promising approach to tackle this problem is chemical synthesis inside nanocapsules, although enzyme-like control of such chemistry has not yet been achieved. In order to better understand the complex chemistry inside nanocapsules, we design a multiscale nanoreactor simulation approach. The nanoreactor simulation protocol consists of hybrid quantum mechanics-molecular mechanics-based high temperature Langevin molecular dynamics simulations. Using this approach we model the tail-to-head formation of monoterpenes inside a resorcin[4]arene-based capsule (capsule I). We provide a rationale for the experimentally observed kinetics of monoterpene product formation and product distribution using capsule I, and we explain why additional stable monoterpenes, like camphene, are not observed. On the basis of the in-capsule I simulations, and mechanistic insights, we propose that feeding the capsule with pinene can yield camphene, and this proposal is verified experimentally. This suggests that the capsule may direct the dynamic reaction cascades by virtue of π-cation interactions.
Desilication of ZSM-5 and ZSM-12 zeolites: Impact on textural, acidic and catalytic properties
Gil, Barbara,Mokrzycki, ?ukasz,Sulikowski, Bogdan,Olejniczak, Zbigniew,Walas, Stanis?aw
, p. 24 - 32 (2010)
Two zeolites of different topology: ZSM-5 and ZSM-12 were subjected to desilication in the NaOH solutions of increasing concentrations. Changes in the properties of modified zeolites were investigated by several methods ( 29Si and 27
-
Ono
, (1927)
-
Synthesis of Terpineol from Alpha-Pinene Catalyzed by α-Hydroxy Acids
Hu, Yi-Ming,Huang, Xiao-Rui,Meng, Zhong-Lei,Qin, Rong-Xiu,Wen, Ru-Si,Zhou, Yong-Hong
, (2022/02/17)
We report the use of five alpha-hydroxy acids (citric, tartaric, mandelic, lactic and glycolic acids) as catalysts in the synthesis of terpineol from alpha-pinene. The study found that the hydration rate of pinene was slow when only catalyzed by alpha-hydroxyl acids. Ternary composite catalysts, composed of AHAs, phosphoric acid, and acetic acid, had a good catalytic performance. The reaction step was hydrolysis of the intermediate terpinyl acetate, which yielded terpineol. The optimal reaction conditions were as follows: alpha-pinene, acetic acid, water, citric acid, and phosphoric acid, at a mass ratio of 1:2.5:1:(0.1–0.05):0.05, a reaction temperature of 70? C, and a reaction time of 12–15 h. The conversion of alpha-pinene was 96%, the content of alpha-terpineol was 46.9%, and the selectivity of alpha-terpineol was 48.1%. In addition, the catalytic performance of monolayer graphene oxide and its composite catalyst with citric acid was studied, with acetic acid used as an additive.
Nickel-catalyzed reductive deoxygenation of diverse C-O bond-bearing functional groups
Cook, Adam,MacLean, Haydn,St. Onge, Piers,Newman, Stephen G.
, p. 13337 - 13347 (2021/11/20)
We report a catalytic method for the direct deoxygenation of various C-O bond-containing functional groups. Using a Ni(II) pre-catalyst and silane reducing agent, alcohols, epoxides, and ethers are reduced to the corresponding alkane. Unsaturated species including aldehydes and ketones are also deoxygenated via initial formation of an intermediate silylated alcohol. The reaction is chemoselective for C(sp3)-O bonds, leaving amines, anilines, aryl ethers, alkenes, and nitrogen-containing heterocycles untouched. Applications toward catalytic deuteration, benzyl ether deprotection, and the valorization of biomass-derived feedstocks demonstrate some of the practical aspects of this methodology.
