Topic
Isobutylene
About: Isobutylene is a research topic. Over the lifetime, 3281 publications have been published within this topic receiving 32262 citations. The topic is also known as: Isopropylidenemethylene & Isobutylene.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this paper, a symmetric telechelic polyisobutylenes (PIB-Cl) was synthesized based on the use of inifers, i.e., bifunctional initiator-transfer agents that effect controlled initiation and propagation.
Abstract: Detailed understanding of the mechanism of initiation and chain transfer in BCl3-coinitiated isobutylene polymerization led to the efficient synthesis of symmetric telechelic polyisobutylenes carrying ∼CH2C(CH3)2Cl groups at either end of the molecule Cl-PIB-Cl. The synthesis is based on the use of inifers, i.e., bifunctional initiator-transfer agents that effect controlled initiation and propagation in the absence of chain transfer to a monomer. Specifically, the synthesis of Cl-PIB-Cl was achieved by the p-dicumyl chloride/BCl3/isobutylene/CH2Cl2 system. According to the inifer mechanism each Cl-PIB-Cl contains two terminal tertiary chlorines and one phenyl group at the interior of the chains. The structure of this new symmetric telechelic polymer has been established by detailed characterization studies including a sensitive new gel permeation chromatography (UV plus RI) analysis method, 1H-NMR, kinetic experiments, and chemical derivatization. The Cl-PIB-Cl molecule is a key intermediate for the synthesis of hosts of new materials, e.g., triblock copolymers, α,ω-diolefins, and α,ω-difunctional polymers.
240 citations
Patent•
31 Oct 1997TL;DR: In this article, triglycerides are reacted in a liquid phase reaction with methanol and a homogeneous basic catalyst, yielding a spatially separated two phase result with an upper located non-polar phase consisting principally of nonpolar methyl esters and a lower located phase consisting of glycerol.
Abstract: Triglycerides are reacted in a liquid phase reaction with methanol and a homogeneous basic catalyst. The reaction yields a spatially separated two phase result with an upper located non-polar phase consisting principally of non-polar methyl esters and a lower located phase consisting principally of glycerol and residual methyl esters. The glycerol phase is passed through a strong cationic ion exchanger to remove anions, resulting in a neutral product which is flashed to remove methanol and which is reacted with isobutylene in the presence of a strong acid catalyst to produce glycerol ethers. The glycerol ethers are then added back to the upper located methyl ethyl ester phase to provide an improved biodiesel fuel.
226 citations
TL;DR: In this article, the effect of macroreticular and gel-type ion exchange resins (Amberlysts) on glycerol tert-butylation was investigated.
Abstract: The etherification of glycerol with isobutylene or tert-butyl alcohol without solvent in the liquid phase catalysed by strong acid ion-exchange resins of Amberlyst type and by two large-pore zeolites H-Y and H-Beta was studied. The swelling of commercial macroreticular and gelular ion-exchange resins (Amberlysts) and its influence on glycerol tert-butylation is discussed in this work. By comparing the conversions of glycerol and selectivity to glycerol di- and tri-tert-butyl ethers for macroreticular and gel type ion-exchange resins, it can be concluded that acid macroreticular resins in dry form are very active catalysts for etherification reaction with isobutylene because of large pore diameter. tert-Butyl alcohol as alkylation agent is not suitable because formed reaction water deactivates the catalysts. The zeolites and gel type polymer catalysts are not effective for this etherification reaction (small pore diameter). The best results of glycerol tert-butylation by isobutylene at 100% conversion of glycerol with selectivity to di- and tri-ethers larger than 92% were obtained over strong acid macroreticular ion-exchange resins. Di- and tri-tert-butyl ethers of glycerol are potential oxygenates to diesel fuel.
222 citations
TL;DR: In this article, sulfonic acid-functionalized mesostructured silicas have demonstrated an excellent catalytic behavior in the etherification of glycerol with isobutylene to yield tert-butylated derivates.
Abstract: Sulfonic-acid-functionalized mesostructured silicas have demonstrated an excellent catalytic behavior in the etherification of glycerol with isobutylene to yield tert-butylated derivates. Di-tert-butylglycerols (DTBG) and tri-tert-butylglycerol (TTBG) have shown to be valuable fuel additives leading to decreases in the emission of particulate matter, hydrocarbons, carbon monoxide and unregulated aldehydes. Likewise, said ethers can also act as cold flow improvers for use in biodiesel, reducing also its viscosity. The activities and selectivities achieved over sulfonic acid-functionalized mesostructured silicas are comparable or even superior to those displayed by widely used macroporous commercial acid resins. Under optimized reaction conditions, these mesostructured catalysts yield a complete glycerol conversion with a combined selectivity towards DTBG and TTBG up to ca. 90%. Furthermore, no formation of undesirable isobutylene oligomers is observed. The acid strength of the sulfonic acid sites has also been found to be an important factor affecting the catalytic performance of these materials.
200 citations
TL;DR: In this article, a (tBu3SiNH)3ZrCl (1-Cl) with RMgX or RLi (R = Me, Et, Cy, CH 2Ph, allyl, CHCH2, Ph, CH2tBu, C⋮CPh, C ⋮CtBu), through addition of isobutylene, H2CCCMe2, and acetylene to 1-H (iBu, dma, or CHCH 2), and by CH-bond activation, produced putative (t
Abstract: Hydrocarbyl complexes, (tBu3SiNH)3ZrR (1-R), were prepared via metatheses of (tBu3SiNH)3ZrCl (1-Cl) with RMgX or RLi (R = Me, Et, Cy, CH2Ph, allyl, CHCH2, Ph, CH2tBu, C⋮CPh, C⋮CtBu), through addition of isobutylene, H2CCCMe2, and acetylene to 1-H (R = iBu, dma, or CHCH2), and by CH-bond activation; thermal 1,2-RH-elimination from 1-R produced putative (tBu3SiNH)2ZrNSitBu3 (2), which was subsequently trapped by R‘H. Thermolysis of 1-R (∼100 °C, R = Me or Cy) in the presence of H2, c-C3H6, and CH4 in cyclohexane or neat C6H6, mesitylene, and toluene afforded 1-R (R = H, cPr, Me, Ph, CH2-3,5-Me2C6H3) and a mixture of 1-CH2Ph and 1-C6H4Me, respectively. Exposure of 1-Cy to C2H4 or C6H6 in cyclohexane provided 1-CHCH2 or 1-Ph, respectively, but further reaction produced 12-(trans-HCCH) and 12-(p-C6H4) through double CH-bond activation. Thermolysis of (tBu3SiND)3ZrCH3 (1-(ND)3-CH3) in C6H6 or C6D6 yielded CH3D, and 1C6H5 or 1-(ND)3C6D5, through reversible benzene activation. Thermolysis of 1-Cy in neat cyclohex...
195 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 16 |
| 2024 | 7 |
| 2023 | 29 |
| 2022 | 43 |
| 2021 | 33 |
| 2020 | 45 |