17410-45-6Relevant articles and documents
Photochemical Transformations. 30. Photosolvolysis of Benzyl Chlorides in tert-Butyl Alcohol. 2. Nature of Excited States
Cristol, Stanley J.,Bindel, Thomas H.
, p. 7287 - 7293 (1981)
The photosolvolysis of a number of benzyl chlorides in tert-butyl alcohol, both as a result of direct irradiation and ketone triplet sensitization, has been studied.A variety of sensitization and quenching techniques have been used.The results obtained are rationalized by the assumption that there are two triplet states of the benzyl chlorides accessible in these experiments - one a short-lived upper state, which leads to solvolysis product, and another a long-lived (lower energy) state, which reverts to ground-state reactant.Consistent with this idea, m-methoxybenzyl chloride is shown to quench the photoreactions of benzopenone with benzhydrol without the formation of a significant amount of reactive species.The effects of wavelength on the reactions of p-acetobenzyl chloride are mesured and discussed in terms of the two-triplet concept.
Evidence for a 1,4 Hydrogen Shift in 2 Deuterium-Labeled Vinyl Carbene Intermediate in the Formation of 1,3-Pentadiene from 3,5-Dimethylpyrazole
Perez, Jorge D.,Yranzo, Gloria L.
, p. 2221 (1982)
The formation of 1,3-pentadiene via a 1,4 hydrogen shift from a deuterium-labeled vinylcarbene intermediate is demonstrated in the thermolysis of 3,5-dimethylpyrazole.
Dehydra-decyclization of 2-methyltetrahydrofuran to pentadienes on boron-containing zeolites
Dauenhauer, Paul J.,Kumar, Gaurav,Liu, Dongxia,Ren, Limin,Tsapatsis, Michael,Xu, Dandan
, p. 4147 - 4160 (2020)
1,3-Pentadiene (piperylene) is an important monomer in the manufacturing of adhesives, plastics, and resins. It can be derived from biomass by the tandem ring-opening and dehydration (dehydra-decyclization) of 2-methyltetrahydrofuran (2-MTHF), but competing reaction pathways and the formation of another isomer (1,4-pentadiene) have limited piperylene yields to MFI > BEA at a given temperature (523 K), indicating the non-identical nature of active sites in these weak solid acids. The diene distribution remained far from equilibrium and was tuned towards the desirable conjugated diene (1,3-pentadiene) by facile isomerization of 1,4-pentadiene. This tuning capability was facilitated by high bed residence times, as well as the smaller micropore sizes among the zeolite frameworks considered. The suppression of competing pathways, and promotion of 1,4-pentadiene isomerization events lead to a hitherto unreported ～86percent 1,3-pentadiene yield and an overall ～89percent combined linear C5 dienes' yield at near quantitative (～98percent) 2-MTHF conversion on the borosilicate B-MWW, without a significant reduction in diene selectivities for at least 80 hours time-on-stream under low space velocity (0.85 g reactant per g cat. per h) and high temperature (658 K) conditions. Finally, starting with iso-conversion levels (ca. 21-26percent) and using total turnover numbers (TONs) accrued over the entire catalyst lifetime as the stability criterion, borosilicates were demonstrated to be significantly more stable than aluminosilicates under reaction conditions (～3-6× higher TONs).
Production of renewable 1,3-pentadiene from xylitol via formic acid-mediated deoxydehydration and palladium-catalyzed deoxygenation reactions
Sun, Ruiyan,Zheng, Mingyuan,Li, Xinsheng,Pang, Jifeng,Wang, Aiqin,Wang, Xiaodong,Zhang, Tao
, p. 638 - 642 (2017)
A two-step synthetic approach for the production of renewable 1,3-pentadiene was reported: xylitol deoxydehydration (DODH) by formic acid to 2,4-pentadien-1-ol, 1-formate (2E), followed by deoxygenation to 1,3-pentadiene over Pd/C. The overall carbon yield of 1,3-pentadiene reached 51.8% under the optimized conditions.
Thermochemical Acidities in Three Superbase Systems
Arnett, Edward M.,Venkatasubramaniam, K. G.
, p. 1569 - 1578 (1983)
Heats of deprotonation (ΔHD) are compared for a number of weak carbon and nitrogen acids in dimethyl sulfoxide (Me2SO) with potassium salts of tert-butyl alcohol (KOBu-t) or the solvent (KMe2SYL) as bases and also for the potassium salt of 1,3-diaminopropane in the diamine (KAPA) as the solvent.For compounds which were deprotonated in all three media, ΔHD values in KAPA are about 9 kcal/mol more exothermic than those in KMe2SYL/Me2SO which in turn are about 4 kcal/mol more exothermic than those in KOBu-t/Me2SO.The heat of isomerization of 1,4-pentadiene to its 1,3-isomer in KAPA is calculated from heats of deprotonation values of the two compounds and found to be 7.96 kcal/mol.This compares well with literature estimates.Resonance energies are estimated for cyclopentadienyl and indenyl anions to be 31.7 and 19.2 kcal/mol, respectively.Heats of deprotonation for a large number of acids in the three bases are compared with free energies of ionization in dimethyl sulfoxide and cyclohexylamine and with heats of ionization in the gas phase.
Production of renewable 1,3-pentadiene over LaPO4 via dehydration of 2,3-pentanediol derived from 2,3-pentanedione
Bai, Chenxi,Cui, Long,Dai, Quanquan,Feng, Ruilin,Liu, Shijun,Qi, Yanlong
, (2022/02/07)
1,3-Pentadiene plays an extremely important role in the production of polymers and fine chemicals. Herein, the LaPO4 catalyst exhibits excellent catalytic performance for the dehydration production of 1,3-pentadiene with 2,3-pentanediol, a C5 diol platform compound that can be easily obtained by hydrogenation of bio-based 2,3-pentanedione. The relationships of catalyst structure-acid/base properties-catalytic performance was established, and an acid-base synergy effect was disclosed for the on-purpose synthesis of 1,3-pentadiene. Thus, a balance between acid and base sites was required, and an optimized LaPO4 with acid/base ratio of 2.63 afforded a yield of 1,3-pentadiene as high as 61.5% at atmospheric pressure. Notably, the Br?nsted acid sites with weak or medium in LaPO4 catalyst can inhibit the occurrence of pinacol rearrangement, resulting in higher 1,3-pentadiene production. In addition, the investigation on reaction pathways demonstrated that the E2 mechanism was dominant in this dehydration reaction, accompanied by the assistance of E1 and E1cb.
Asymmetric Counteranion Directed Catalytic Heck/Tsuji-Trost Annulation of Aryl Iodides and 1,3-Dienes
Xu, Jia-Cheng,Yin, Yi-Zhuo,Han, Zhi-Yong
supporting information, p. 3834 - 3838 (2021/05/26)
A chiral anion-mediated asymmetric Heck/Tsuji-Trost reaction of aryl iodides and 1,3-dienes is presented. Chiral indoline derivatives could be afforded with remarkably higher yields and enantioselectivities than our previous chiral ligand-based method. Silver carbonate is employed as both base and halide scavenger to ensure fast and recyclable exchange of the catalytic amount of chiral anions. Fast salt metathesis, as well as the acceleration effect of the chiral anion, could both benefit the stereocontrol of the reaction.
CATALYTIC HYDROCARBON DEHYDROGENATION
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Paragraph 0056; 0122; 0123, (2021/03/13)
A catalyst for dehydrogenation of hydrocarbons includes a support including zirconium oxide and Linde type L zeolite (L-zeolite). A concentration of the zirconium oxide in the catalyst is in a range of from 0.1 weight percent (wt. %) to 20 wt. %. The catalyst includes from 5 wt. % to 15 wt. % of an alkali metal or alkaline earth metal. The catalyst includes from 0.1 wt. % to 10 wt. % of tin. The catalyst includes from 0.1 wt. % to 8 wt. % of a platinum group metal. The alkali metal or alkaline earth metal, tin, and platinum group metal are disposed on the support.
Synthesis method of pentanediol, and synthesis method for preparing biomass-based pentadiene through conversion of levulinic acid and derivatives of levulinic acid
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Paragraph 0157; 0161-0165; 0170; 0174-0177; 0178; 0182-0185, (2021/04/07)
The invention provides a synthesis method of pentanediol, and the method comprises the following steps: carrying out conversion reaction on a mixed solution obtained by mixing levulinic acid and/or levulinic acid derivatives, a catalyst and an organic solvent in a hydrogen-containing atmosphere to obtain the pentanediol. According to the method, a large amount of cheap and easily available bio-based chemical levulinic acid or derivatives thereof can be utilized, pentanediol is obtained through catalytic conversion, and m-pentadiene is further obtained. The raw materials are derived from renewable resources, the m-pentadiene is prepared through hydrogenation and dehydration, and particularly, a green and sustainable process route for synthesizing the m-pentadiene is finally obtained through a dehydration reaction route and construction of a dehydration catalyst. The invention provides a method for green and sustainable synthesis of linear pentadiene based on bio-based chemical conversion, and the method has the advantages of simple operation, short flow, no need of harsh experimental conditions, easy preparation of raw materials and catalysts, and large-scale synthesis prospect.
Synthesis method of pentanediol and synthesis method for preparing biomass-based linear pentadiene based on lactic acid conversion
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Paragraph 0204; 0209-0210; 0211; 0216-0217; 0218; 0223-0224, (2021/05/19)
The invention provides a method for synthesizing pentanediol. The method comprises the following steps: carrying out hydrogenation reaction on a mixed solution obtained by mixing pentanedione, a hydrogenation catalyst and an organic solvent in a hydrogen-containing atmosphere to obtain the pentanediol. According to the invention, a large amount of cheap and easily available bio-based chemical lactic acid can be utilized to obtain pentanediol, and linear pentadiene is further obtained; the raw materials are from renewable resources, and linear pentadiene is obtained through the following steps: (1) condensing lactic acid to prepare pentanedione, (2) hydrogenating pentanedione to prepare pentanediol, and (3) dehydrating pentanediol to obtain linear pentadiene; linear pentadiene, especially 1, 3-pentadiene, is prepared from lactic acid through a process route of condensation, hydrogenation and dehydration; and a green and sustainable linear pentadiene synthesis method based on bio-based chemical conversion is provided, and is simple to operate, short in process, free of harsh experimental conditions, easy to prepare raw materials and catalysts, and has a large-scale synthesis prospect.
