592-77-8Relevant articles and documents
Directing the Rate-Enhancement for Hydronium Ion Catalyzed Dehydration via Organization of Alkanols in Nanoscopic Confinements
Shetty, Manish,Wang, Huamin,Chen, Feng,Jaegers, Nicholas,Liu, Yue,Camaioni, Donald M.,Gutiérrez, Oliver Y.,Lercher, Johannes A.
supporting information, p. 2304 - 2311 (2020/12/01)
Alkanol dehydration rates catalyzed by hydronium ions are enhanced by the dimensions of steric confinements of zeolite pores as well as by intraporous intermolecular interactions with other alkanols. The higher rates with zeolite MFI having pores smaller than those of zeolite BEA for dehydration of secondary alkanols, 3-heptanol and 2-methyl-3-hexanol, is caused by the lower activation enthalpy in the tighter confinements of MFI that offsets a less positive activation entropy. The higher activity in BEA than in MFI for dehydration of a tertiary alkanol, 2-methyl-2-hexanol, is primarily attributed to the reduction of the activation enthalpy by stabilizing intraporous interactions of the Cβ-H transition state with surrounding alcohol molecules. Overall, we show that the positive impact of zeolite confinements results from the stabilization of transition state provided by the confinement and intermolecular interaction of alkanols with the transition state, which is impacted by both the size of confinements and the structure of alkanols in the E1 pathway of dehydration.
PROCESSES FOR CONVERTING NAPHTHA TO DISTILLATE PRODUCTS
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Paragraph 0179, (2020/07/14)
The present disclosure provides processes to convert heavy hydrocarbons to light distillates. The present disclosure further provides compositions including light distillates. In an embodiment, a process for upgrading a hydrocarbon feed includes dehydrogenating a C3-C50 cyclic alkane and an C2-C50 acyclic alkane in the presence of a dehydrogenation catalyst to form a C3-C50 cyclic olefin and a C2-C50 acyclic olefin. The process includes reacting the C3-C50 cyclic olefin and the C2-C50 acyclic olefin in the presence of a group 6 or group 8 transition metal catalysts to form a C5-C200 olefin. The process further includes hydrogenating the C5-C200 olefin in the presence of a hydrogenation catalyst to form a C5-C200 hydrogenated product. Processes of the present disclosure may further include hydroisomerizing the C5-C200 hydrogenated product in the presence of a hydroisomerization catalyst to form a C5-C200 hydroisomerized product.
Olefin Dimerization and Isomerization Catalyzed by Pyridylidene Amide Palladium Complexes
Navarro, Miquel,Rosar, Vera,Montini, Tiziano,Milani, Barbara,Albrecht, Martin
, p. 3619 - 3630 (2018/10/05)
A series of cationic palladium complexes [Pd(N^N′)Me(NCMe)]+ was synthesized, comprising three different N^N′-bidentate coordinating pyridyl-pyridylidene amide (PYA) ligands with different electronic and structural properties depending on the PYA position (o-, m-, and p-PYA). Structural investigation in solution revealed cis/trans isomeric ratios that correlate with the donor properties of the PYA ligand, with the highest cis ratios for the complex having the most donating o-PYA ligand and lowest ratios for that with the weakest donor p-PYA system. The catalytic activity of the cationic complexes [Pd(N^N′)Me(NCMe)]+ in alkene insertion and dimerization showed a strong correlation with the ligand setting. While complexes bearing more electron donating m- and o-PYA ligands produced butenes within 60 and 30 min, respectively, the p-PYA complex was much slower and only reached 50% conversion of ethylene within 2 h. Likewise, insertion of methyl acrylate as a polar monomer was more efficient with stronger donor PYA units, reaching a 32% ratio of methyl acrylate vs ethylene insertion. Mechanistic investigations about the ethylene insertion allowed detection, for the first time, by NMR spectroscopy both cis- and trans-Pd-ethyl intermediates and, furthermore, revealed a trans to cis isomerization of the Pd-ethyl resting state as the rate-limiting step for inducing ethylene conversion. These PYA palladium complexes induce rapid double-bond isomerization of terminal to internal alkenes through a chain-walking process, which prevents both polymerization and also the conversion of higher olefins, leading selectively to ethylene dimerization.
Z-Selective alkyne semi-hydrogenation catalysed by piano-stool N-heterocyclic carbene iron complexes
Johnson, Chloe,Albrecht, Martin
, p. 2779 - 2783 (2018/06/14)
NHC iron(ii) piano-stool complexes catalyse the selective semi-hydrogenation of alkynes to alkenes using silanes as reducing agents. Aromatic terminal alkynes are converted to styrenes without over-reduction to ethylbenzene derivatives. Furthermore, internal aryl alkynes afford cis-alkenes with excellent Z-selectivity.
Synthesis, structure and thermolysis of cis-dialkylplatinum(II) complexes - Experimental and theoretical perceptions
Venkatesh, Sadhana,Sravani, Chinduluri,Janardan, Sannapaneni,Suman, Pothini,Goud, E. Veerashekhara,Pavankumar,Leninkumar, Vardi,Bhat, Haamid R.,Sivaramakrishna, Akella,Vijayakrishna, Kari,Jha, Prakash C.,Smith, Gregory S.
, p. 72 - 81 (2016/07/06)
The formation of new C-C bonds by metal complexes always stimulates great interest because these fundamental reaction types possess numerous potential applications in organic synthesis. These reactions are well documented for a variety of transition metal complexes. Herein we report synthesis and characterization of a series of platinum-dialkyl complexes (1-10) of the type [Pt(L2)R2], (where L2 = dppp (1,3-bis(diphenylphosphino)propane or L = PPh3; R = n-butyl to n-nonyl) with a view to understand the organic product distribution patterns on thermolysis. The single crystal X-ray structures of the complexes [Pt(dppp){CH2(CH2)3CH3}2] (1) and [Pt(dppp){CH2(CH2)6CH3}2] (7) are reported. Thermal decomposition studies of these complexes show interesting behaviour; the longer chain dialkyls i.e. C7-C9 complexes undergo reductive elimination whereas the shorter chain dialkyl complexes and C3-C6 prefer only the β-hydride elimination reaction. Possible mechanistic aspects are discussed. Theoretical calculations reveal the strongest delocalizations in both complexes involve the interaction of Pt-C bond pair electron density with the trans positioned Pt-P antibonding orbital and vice-versa.
Oxygen-Deficient Tungsten Oxide as Versatile and Efficient Hydrogenation Catalyst
Song, Jiajia,Huang, Zhen-Feng,Pan, Lun,Zou, Ji-Jun,Zhang, Xiangwen,Wang, Li
, p. 6594 - 6599 (2015/11/18)
Heterogeneous hydrogenation is one of the most important industrial operations, and reduced metals (mostly noble metals and a few inexpensive metals) generally serve as the catalyst to activate molecular H2. Herein we report oxygen-deficient tungsten oxide, such as WO2.72, is a versatile and efficient catalyst for the hydrogenation of linear olefins, cyclic olefins, and aryl nitro groups, with obvious advantages compared with non-noble metal nickel catalyst from the aspect of activity and selectivity. Density functional theory calculations prove the oxygen-deficient surface activates H2 very easily in both kinetics and thermodynamics. Testing on several oxygen-deficient tungsten oxides shows a linear dependence between the hydrogenation activity and oxygen vacancy concentration. Tungsten is earth-abundant, and WO2.72 can be synthesized in large scale using a low-cost procedure, which provides an ideal catalyst for industrial application. Because oxygen vacancy is a common characteristic of many metal oxides, the findings in this work may be extended to other metal oxides and thus provide the possibility for exploring a new type of hydrogenation catalyst.
One-pot production of hydrocarbon oil from poly(3-hydroxybutyrate)
Kang, Shimin,Yu, Jian
, p. 14320 - 14327 (2014/04/17)
Poly(3-hydroxybutyrate) (PHB) is an energy storage material of many microbial species, and has been found to be an effective feedstock for production of renewable hydrocarbon oils. A high oil yield (up to 38.2 wt%) was obtained in a phosphoric acid (H3PO4) solution at mild temperatures (165-240 °C). PHB and crotonic acid (C4H 6O2), a dominant thermal degradation product of PHB, were deoxygenated mainly via decarboxylation, generating similar liquid and gaseous products. Carbon dioxide and propylene were the major products in gas phase with little CO formation. The hydrocarbon oil (C4-C16) is a mixture of alkanes, alkenes, benzenes and naphthalenes. Aromatics (C10-C15) were the major hydrocarbons in a 100 wt% H3PO4 solution, while alkenes and alkanes (C4-C9) were favored in diluted solutions (50 wt% to 85 wt% H 3PO4). The concentration of H3PO4 was a key factor that affected the oil composition and yield. A highly efficient decarboxylation of crotonic acid at 220 °C for 3 hours resulted in 70.8 wt% of oxygen being removed as CO2 and 57.0 wt% of carbon being recovered as hydrocarbon oil. The H3PO4 solution can be repeatedly used for high yield oil production. This work shows that a type of new biological feedstock can be used to produce renewable hydrocarbon oil in an efficient one-pot reaction. This journal is the Partner Organisations 2014.
Thermolysis studies on platinacycloalkane complexes
Zheng, Feng,Sivaramakrishna, Akella,Moss, John R.
scheme or table, p. 2457 - 2465 (2011/06/26)
Thermal decomposition studies on platinacycloalkanes of the type Pt(CH 2)mL2 (where m = 6,7,8,10 and L2 = dppp {1,3-bis(diphenylphosphino)propane}, dppe {1,2-bis(diphenylphosphino) ethane} or L = PPh3, tBu3P) are described. The results reveal that the organic product distribution depends on various factors such as the nature of ligand, the metal system, the mode of decomposition, the ring size and the temperature. Possible mechanistic pathways for the formation of various products are discussed. These platinacycloalkanes can be used as models for metallacycloalkane intermediates in catalytic reactions.
The first example of tungsten-based carbene generation from WCl6 and atomic carbon and its use in olefin metathesis
Düz, Bülent,Yüksel, Dilek,Ece, Abdulilah,Sevin, Fatma
, p. 5167 - 5170 (2007/10/03)
We describe a new route for the synthesis of tungsten-based carbenes generated by the reaction of WCl6 with atomic carbon in a carbon arc reactor. The active species formed under these conditions, [W] = CCl2, was found to catalyze olefin metathesis reactions of 1-octene, 2-octene and 1-heptene. We also evaluated the mechanism of formation of [W] = CCl2 within the WCl6/C system at the DFT level.
1,1,2,2-Tetrafluoroethyl-N,N-dimethylamine: A new selective fluorinating agent
Petrov,Swearingen,Hong,Chris Petersen
, p. 25 - 31 (2007/10/03)
The title compound has been prepared in 96-98% yield by the reaction of tetrafluoroethylene and dimethylamine. 1,1,2,2-Tetrafluoroethyl-N,N-dimethylamine (1) is found to be an effective reagent for the conversion of alcohols into alkyl fluorides. Reaction of 1 and primary alcohols proceeds with high yield formation of the corresponding alkyl fluorides at elevated temperature. However, the reaction of secondary and tertiary alcohols rapidly takes place at 0-10°C, producing corresponding alkyl fluorides as major product along with some olefins.
