- Kinetics of molecular encapsulation of 1-methylcyclopropene into α-cyclodextrin
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1-Methylcyclopropene (1-MCP), an ethylene inhibiting regulator, is commercially available in the form of an inclusion complex with α-cyclodextrin (α-CD). In this study, molecular encapsulation of gaseous 1-MCP into aqueous α-CD was investigated in a closed, agitated vessel with a flat gas-liquid interface. Molecular encapsulation of gaseous 1-MCP by α-CD is a simultaneous two-step reaction which involves the aqueous dissolution of gaseous 1-MCP and the encapsulation of the dissolved molecules by α-CD. The kinetics and mechanism of molecular encapsulation were analyzed based on the depletion rate of 1-MCP in the headspace of the vessel. The encapsulation rates could be explained quantitatively by the gas absorption theory with a pseudo-first-order reaction between 1-MCP and α-CD. The negative value of the calculated apparent activation energy of encapsulation (-24.4 kJ/mol) implied the significant effect of exothermic aqueous dissolution of 1-MCP. An encapsulation temperature of 15°C was optimal; at this temperature, the highest 1-MCP yield and best inclusion ratio of inclusion complex were obtained. Changes in the X-ray diffraction pattern suggested that the crystal lattice structure of α-CD was altered upon inclusion of 1-MCP.
- Tze, Loon Neoh,Yamauchi, Kousuke,Yoshii, Hidefumi,Furuta, Takeshi
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Read Online
- Highly efficient synthesis of methylenecyclopropane
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An efficient procedure for the preparation of methylenecyclopropane (3), a valuable starting material in organic synthesis, has been developed from methallyl chloride (1) and alkali metal [bis(trimethylsilyl)]amide [M(BTMSA) (M = Na, K), 2b,c]. The advantages of this new method are the higher yield of methylenecyclopropane up to 79% and a homogenous reaction mixture, i.e. both substrates are soluble in organic solvents such as toluene and dibutyl ether.
- Binger, Paul,Brinkmann, Axel,Wedemann, Petra
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Read Online
- METHODS FOR GENERATING PURIFIED CYCLOPROPENES
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The present invention relates to methods of preparing purified cyclopropylene (1-methylcyclopropylene) gas employing one or more non-reactive purification processes to purify substances including, without limitation, cyclopropene (1-methylcyclopropylene) gas and/or lithio-cyclopropene.
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Paragraph 0039; 0042
(2021/02/19)
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- Activation and Functionalization of C-C σ Bonds of Alkylidene Cyclopropanes at Main Group Centers
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Aluminum(I) and magnesium(I) compounds are reported for the C-C σ-bond activation of strained alkylidene cyclopropanes. These reactions result in the formal addition of the C-C σ bond to the main group center either at a single site (Al) or across a metal-metal bond (Mg-Mg). Mechanistic studies suggest that rather than occurring by a concerted oxidative addition, these reactions involve stepwise processes in which substrate binding to the main group metal acts as a precursor to α- or β-alkyl migration steps that break the C-C σ bond. This mechanistic understanding is used to develop the magnesium-catalyzed hydrosilylation of the C-C σ bonds of alkylidene cyclopropanes.
- Crimmin, Mark R.,Kong, Richard Y.
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p. 11967 - 11971
(2020/08/06)
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- Stereo- and Regioselective 1,3-Dipolar Cycloaddition of the Stable Ninhydrin-Derived Azomethine Ylide to Cyclopropenes: Trapping of Unstable Cyclopropene Dipolarophiles
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A stereo- and regioselective 1,3-dipolar cycloaddition of the stable ninhydrin-derived azomethine ylide [2-(3,4-dihydro-2H-pyrrolium-1-yl)-1-oxo-1H-inden-3-olate, DHPO] to differently substituted cyclopropenes has been established. As a result, an efficient synthetic protocol was developed for the preparation of biologically relevant spiro[cyclopropa[a]pyrrolizine-2,2′-indene] derivatives. DHPO has proved to be an effective trap for such highly reactive and unstable substrates as parent cyclopropene, 1-methylcyclopropene, 1-phenylcyclopropene, and 1-halo-2-phenylcyclopropenes. It has also been found that 3-nitro-1,2-diphenylcyclopropene undergoes a nucleophilic substitution reaction in alcohols and thiols to afford 3-alkoxy- and 3-arylthio-substituted 1,2-diphenylcyclopropenes, which can be captured as corresponding 1,3-dipolar cycloadducts in the presence of DHPO. These new approaches provide a straightforward strategy for the synthesis of functionally substituted cyclopropa[a]pyrrolizine derivatives. The factors governing regio- and stereoselectivity have been revealed by means of quantum mechanical calculations (M11 density functional theory), including previously unreported Nylide-Hcyclopropene second-orbital interactions. The outcome of this work contributes to the study of 1,3-dipolar cycloaddition, as well as enriches chemistry of cyclopropenes and methods for the construction of polycyclic compounds with cyclopropane fragments.
- Filatov, Alexander S.,Wang, Siqi,Khoroshilova, Olesya V.,Lozovskiy, Stanislav V.,Larina, Anna G.,Boitsov, Vitali M.,Stepakov, Alexander V.
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p. 7017 - 7036
(2019/06/14)
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- DEVICE FOR GENERATING ULTRA PURE 1-METHYLCYCLOPROPENE
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The present invention relates to a device for generating ultra pure 1-methyl-cyclopropene (1 -MCP) by using an improved carrier gas flow control system. The invention also relates to the use of a 1-MCP generating device for inhibiting the action of ethylene which accelerates the ripening process of plants such as fruits, flowers, vegetables and the like. Furthermore the invention encompasses a method for treating and storing harvested agricultural products using said 1-MCP generating device.
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Paragraph 11-12
(2019/01/10)
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- Preparation method of 1-methylcyclopropene
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The invention discloses a preparation method of 1-methylcyclopropene. 3-chloro-2-methacrylonitrile generates a ring-closure reaction under the effect of a NaH strong base catalyst with methylbenzene as a solvent, 1-methylcyclopropene sodium salt is generated and precipitated from the solvent methylbenzene, surplus raw materials and byproducts are left in the solvent, the raw materials and the solvent can be recycled through simple distillation to be cyclically used indiscriminately, the sodium salt is decomposed with water, and high-purity 1-methylcyclopropene can be obtained.
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Paragraph 0022-0025
(2017/08/31)
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- COMPOSITIONS FOR CONTROLLED RELEASE OF ACTIVE INGREDIENTS AND METHODS OF MAKING SAME
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Compositions for controlled release of active ingredients and methods of making same are generally provided. In some embodiments, the composition comprises an active ingredient and a delivery material. In some embodiments, the composition comprises a volatile or gaseous active ingredient useful for applications in at least one of agriculture, pest control, odor control, and food preservation. In some embodiments, the active ingredient is a cyclopropene. In some embodiments, the active ingredient is an essential oil, a terpene, or a terpenoid. In some embodiments, the delivery material is a carbon material or a silicate material.
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Page/Page column 49
(2017/09/08)
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- COMPLEXES OF 1-METHYLCYCLOPROPENE WITH METAL COORDINATION POLYMER NETWORKS
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Disclosed are adsorption complexes that include 1-methylcyclopropene (1-MCP) and a metal coordination polymer network (MCPN), wherein the MCPN is a porous material, and the 1-MCP is adsorbed into the MCPN. Also disclosed are kits for containing 1-MCP that include the adsorption complex in a 1-MCP-impermeable package. Also disclosed are methods of releasing 1-methylcyclopropene (1-MCP) from the kit that include the application of aqueous fluids, heat, and/or pressure.
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Paragraph 0054
(2016/06/06)
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- Boron Complexes With Gradual 1- Methylcyclopropene Releasing Capability
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Compounds having one of the following formulae: wherein R1 and R2 are alkyl or aryl and R1 and R2 may be the same or different, wherein R1 is alkyl o aryl, or wherein alkyl is a liner or branched, saturated or unsaturated alkyl having C1-20 and wherein aryl is an aromatic ring having C1-15. Also methods of using the compounds, including method of inhibiting and ethylene response in a plant.
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Paragraph 0052
(2016/03/09)
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- APPARATUS FOR GENERATING 1-METHYLCYCLOPROPENE
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Provided is an apparatus for generating 1-methylcyclopropene. The apparatus of the present invention may enable the immediate and convenient generation of 1-methylcyclopropene in a desired location using stable 1-methylcyclopropene precursors.
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Paragraph 0055; 0056
(2014/02/16)
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- CYCLOPROPENES-GENERATING DEVICES TO CONTROL RIPENING PROCESSES OF AGRICULTURAL PRODUCTS
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Provided is a device for generation of cyclopropene compounds which is capable of achieving direct in situ preparation and application of cyclopropene compounds inhibiting the action of ethylene which accelerates the ripening process of plants, the device comprising a first storage part for storing precursors of cyclopropene compounds (“cyclopropene precursors”), a second storage part for storing reaction reagents which convert cyclopropene precursors into cyclopropene derivatives via chemical reaction, and a spray part for spraying the cyclopropene derivatives produced by the chemical reaction between the cyclopropene precursors and the reaction reagents.
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Page/Page column 7
(2012/06/01)
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- METHOD OF PREPARING 1-METHYLCYCLOPROPENE AND APPLYING THE SAME TO PLANTS
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Disclosed is a method for directly preparing in situ 1-methylcyclopropene which inhibits the action of ethylene of accelerating the ripening process of plants, which comprises reacting a predetermined 1-methylcyclopropene precursor represented by the following Formula 2 or 3 with a base or fluoride anion material, and applying the 1-methylcyclopropene to plants: wherein Me, Et, R1, R2 and X are defined in the specification.
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Page/Page column 7-8
(2010/04/23)
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- Stable ethylene inhibiting compounds and methods for their preparation
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A method to inhibit the ethylene response in plants with cyclopropene compounds by first generating stable cyclopropane precursor compounds and then converting these compounds to the gaseous cyclopropene antagonist compound by use of a reducing or nucleophilic agent.
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- STEREOCHEMISTRY AND MECHANISM OF CYCLOPROPENE RING OPENING IN REACTIONS OF CYCLOPROPENE COMPOUNDS WITH ELECTROPHILES. STEREOCHEMISTRY OF ADDITION OF 2,4-DINITROBENZENESULFENYL CHLORIDE TO 1-METHYLCYCLOPROPENE
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Cyclopropene ring opening in reactions of 1-methylcyclopropene with electrophilic reagents can be proceed with high stereoselectivity.The configuration of the products depends on the nature of the electrophile.Reaction with deuterium chloride gave products with the Z-configuration.In the reaction of 1-methylcyclopropene with reagents that tend to form cyclic intermediates (sulfenyl halides, N-bromosuccinimide, tert-butyl hypochlorite), the cyclopropene ring opened E-stereoselectively.Reaction with bromide gave a mixture of E- and Z- isomers in the ratio 3 : 1.It was established by X-ray structure analysis that 1-methylcyclopropene reacts with 2,4-dinitrobenzenesulfenyl chloride by a Markovnikov trans-addition scheme.Mechanism for the reaction of cyclopropene compounds with electrophiles are proposed and discussed.
- Kartashov, V. R.,Skorobogatova, E. V.,Afanas'ev, P. S.,Chertkov, V. A.,Sergeev, N. M.,et al.
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p. 1639 - 1648
(2007/10/02)
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- Kinetics of the Reaction of CH2(a1A1) with CH3C2H, HCN, CO2, N2O and COS
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The reactions of CH2(a1A1) with CH3C2H, HCN, CO2, N2O and COS are investigated at room temperature.CH2(a1A1) is generated by pulsed laser photolysis of CH2CO.Overall removal rate constants are derived from concentration profiles under first order reaction conditions using direct, time resolved LIF detection of CH2(a1A1).The second order rate constants are found in units of 1E13 cm2/mol s to be 24, 18, 2.0, 3.8 and 20, respectively. - The contribution of physical quenching to the removal of CH2(a1A1) are determined by monitoring directyl the formation of CH2(X3B1) with LMR absorption technique.The branching ratios of collision induced intersystem crossing versus total consumption of 1CH2 are 0.14, 0.32, 0.67, 0.46 and 0.29 for the five reactants.
- Koch, M.,Temps, F.,Wagener, R.,Wagner, H. Gg.
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p. 645 - 650
(2007/10/02)
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- The isomerization of 1-methylcyclopropene: A multichannel unimolecular reaction induced by overtone excitation
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The distribution of products resulting from the isomerization of gas phase 1-methylcyclopropene (1) induced by C-H stretch overtone excitation has been studied in a search for mode specific effects.Quantum yields for the disappearance of 1 have been determined as a function of the total pressure of a mixture of 1 and methylenecyclopropane and of the added bath gases SF6 and Ar using a combination of intracavity dye laser photolysis and end product analysis by gas chromatography.These data, together with the ratios of the yields of the major isomerization products, are adequately reproduced by RRKM theory and a weak collisional energy transfer model: no evidence for mode specifity is obtained.The experimental data demonstrate the importance of inefficient collisional energy transfer but allow some conclusions to be drawn concerning the applicability of RRKM theory which are not strongly dependent upon the details of the energy transfer model.
- Baggott, J. E.,Law, D. W.
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p. 900 - 906
(2007/10/02)
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- Thermal Rearrangements, part XIV. Gas Phase Kinetics of Pyrolysis of 1-Methyl-1-cyclopropene
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The title study has been carried out in the temperature range 210-250 deg C.The isomerisation products are butyne (91-94percent), 1,3-butadiene (5-8percent), and 1,2-butadiene (1-2percent).No other products were detected and material recovery was complete within experimental error (+/- 5percent).The reaction obeyed first-order kinetics, with the products formed by parallel pathways, and appeared to both unimolecular and homogeneous although some surface sensitivity was detected in packed vessels.Studies of pressure dependence showed characteristic rate constant "fall-off" below 20 Torr (SF6) and 100 Torr (N2).Within at least 2percent of the high pressure limit, the following Arrhenius equation for overall decomposition was found: log(k/s-1) = (12.91 +/- 0.15) - (160 +/- 1.5 kJ mol-1)/RTln 10.Arrhenius equations were similarly found for the individual pathways.The figures are discussed in the light of Transition State Theory and represent a significant improvement over a previous study.It is argued that all products arise via 1,2 shifts in a diradical-like intermediate and the propensities for different H shifts are discussed.A 1-methyl substituent, rather surprisingly, deactivates cyclopropene in its isomerisation reactions.
- Hopf, Henning,Wachholz, Gerhard,Walsh, Robin
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p. 3579 - 3587
(2007/10/02)
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- Thiono and Dithio Esters, XXV. - (4+2) Cycloadditions with Dithionooxalates
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O,O-Dimethyl dithiooxalate (1a) reacts as a 2?-component with typical dienes (e.g. 2,3-dimethylbutadiene or cyclopentadiene) as well as with the strained ?-bonds of quadricyclane to form cycloaddition products.With the energy-rich double bonds of norbornene derivatives, cyclopropenes, and benzovalene, 1a as a 4?-component furnishes cycloadducts.With cyclopentene an equilibrium of product and starting material was achieved after two weeks. 1a reacts also with substances containing activated triple bonds such as dehydrobenzene or acetylenedicarboxylic ester.
- Hartke, Klaus,Henssen, Guenter,Kissel, Thomas
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p. 1665 - 1676
(2007/10/02)
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