Liquid Furan Research Articles

Synthesis takes the pressure off carbon nanothreads

Carbon nanothreads are high-strength polymers typically made by squeezing tiny samples of benzene or pyridine in diamond anvil cells under enormous pressures of 23–30 GPa. But this method can produce only nanogram batches of nanothreads—a major roadblock to exploiting their properties. Researchers have now found a way to produce these nanothreads at one-half to one-third the pressures required previously, scaling up their synthesis so they can be investigated in more detail ( ACS Nano 2021, DOI: 10.1021/acsnano.0c10400 ). By using liquid furan as the starting material, Elizabeth Elacqua of Pennsylvania State University and her team can make carbon-based nanothreads at just 10 GPa with a piece of equipment called a Paris-Edinburgh press. Furan has far less aromatic stabilization than benzene and more readily undergoes cycloaddition reactions to build the polymer. The press is larger than a diamond anvil cell and can produce about 5 mg of nanothreads in each run.

Scalable Synthesis of Crystalline One-Dimensional Carbon Nanothreads through Modest-Pressure Polymerization of Furan.

Carbon nanothreads, which are one-dimensional sp3-rich polymers, combine high tensile strength with flexibility owing to subnanometer widths and diamond-like cores. These extended carbon solids are constructed through pressure-induced polymerization of sp2 molecules such as benzene. Whereas a few examples of carbon nanothreads have been reported, the need for high onset pressures (≥17 GPa) to synthesize them precludes scalability and limits scope. Herein, we report the scalable synthesis of carbon nanothreads based on molecular furan, which can be achieved through ambient temperature pressure-induced polymerization with an onset reaction pressure of only 10 GPa due to its lessened aromaticity relative to other molecular precursors. When slowly compressed to 15 GPa and gradually decompressed to 1.5 GPa, a sharp 6-fold diffraction pattern is observed in situ, indicating a well-ordered crystalline material formed from liquid furan. Single-crystal X-ray diffraction (XRD) of the reaction product exhibits three distinct d-spacings from 4.75 to 4.9 Å, whose size, angular spacing, and degree of anisotropy are consistent with our atomistic simulations for crystals of furan nanothreads. Further evidence for polymerization was obtained by powder XRD, Raman/IR spectroscopy, and mass spectrometry. Comparison of the IR spectra with computed vibrational modes provides provisional identification of spectral features characteristic of specific nanothread structures, namely syn, anti, and syn/anti configurations. Mass spectrometry suggests that molecular weights of at least 6 kDa are possible. Furan therefore presents a strategic entry toward scalable carbon nanothreads.

Effect of furanic biofuels on particles formation in premixed ethylene–air flames: An experimental study

Furanic fuels have been recently investigated because they are considered possible fossil fuel substituents due to their high energy density, their renewable origin and consequently low green-house gas emissions. Few data are available about the behaviors of these fuels in laboratory flame reactors. We have recently studied their sooting tendency in a counter-flow diffusion flame showing a different propensity to form particulate matter depending on the richness of the combustion conditions. In this paper, we explore their tendency in forming particulate matter in atmospheric pressure premixed flames burning mixtures of ethylene and furanic fuels at four different equivalence ratios, namely 2.01, 2.16, 2.31 and 2.46, thus covering the range from slightly sooting to fully sooting conditions. Liquid furan, 2-methylfuran and 2,5-dimethylfuran have been added to ethylene as 10% and 20% of the total carbon fed to the flame.In-situ spectroscopy, namely laser UV-induced emission, has been used as diagnostic tool to detected different classes of precursor nanoparticles by changing the detection wavelength from the UV to the visible. Laser induced incandescence has instead been used to detect soot particles. Equivalence ratios, the total carbon flow rate and cold gas velocity have been kept constant, allowing the combustion temperature to be almost the same also when furans were added.LII signal decreases significantly when furans are added showing a strong effect of furanic fuels in decreasing the amount of soot formed in atmospheric pressure premixed flames. Particularly the reduction increases as the equivalence ratio increases. On the other side, LIF UV and LIF VIS slightly decrease when furans are added. The absence of a significant reduction of the LIF UV signal when furans are added suggests that small particle formation is not effectively inhibited by these additives. This behavior is similar to what found for ethanol and dimethyl ether addition to ethylene premixed flames, showing a similarity in the behavior of these oxygenated fuels.

ChemInform Abstract: Pressure and Temperature Study of the Isotropic Raman Spectra for the Symmetric A1 Vibrational Modes of Liquid Furan.

The Raman bands of the symmetric Ar modes of liquid furan have been measured as a function of temperature (-42.0 to 80.8 o C) and pressure (1 bar to 5 kbar). Line widths and peak frequencies of the isotropic spectra are determined for two C-H bending modes, three ring stretching modes, and two C-H stretching modes. More conclusive evidence concerning these assignments are offered since the three types of vibrational modes have distinctive bandwidth and frequency shift trends in response to increasing temperature and pressure

Pressure and temperature study of the isotropic Raman spectra for the symmetric A1 vibrational modes of liquid furan

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPressure and temperature study of the isotropic Raman spectra for the symmetric A1 vibrational modes of liquid furanY. T. Lee, S. L. Wallen, and J. JonasCite this: J. Phys. Chem. 1992, 96, 11, 4282–4288Publication Date (Print):May 1, 1992Publication History Published online1 May 2002Published inissue 1 May 1992https://doi.org/10.1021/j100190a034RIGHTS & PERMISSIONSArticle Views81Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (837 KB) Get e-Alerts

Application of an autoregressive model for the analysis of reorientational motion in polar liquids

An autoregressive time series analysis has been applied to resolve the angular velocity correlation functions of liquid furan and 2,2-dinitropropane. The two main modes obtained from this resolution correspond to two possible motions of the dipole moment of the molecules. The contribution of these motions to the total correlation function and to the rotational diffusion coefficient has been estimated.

Ultrasonic studies of the vibrational relaxation in simple liquid mixtures

The ultrasonic absorption in the liquid furan - 2,5-dihydrofuran, furan - 2,3-dihydrofuran and furan - tetrahydrofuran mixtures have been measured in the frequency range from 10 MHz to 2 GHz at temperatures varying from 273 K to 293 K. The method based on the Herzfeld - Litovitz theory for description of experimental data over the frequency and concentration region is proposed. The results of calculations have been interpreted in terms of VV-, VV′- and VT-processes which determine the vibrational kinetics in liquid mixtures. The observed temperature dependence of the kinetic parameters is also discussed. It is shown that proposed method may be used for the estimation of relaxation times of molecules which have a very short vibrational lifetimes.

Experimental Study on Phase Velocity of Ultrasonic Waves Decaying in Space and in Time

Modified system of high-resolution Bragg reflection was used to observe both the spatial and temporal sound waves simultaneously in the relaxation region of liquid furan (${\mathrm{C}}_{4}$${\mathrm{H}}_{4}$O). The spatial phase velocity at 100 MHz was shown to be higher than the temporal velocity by 7 m/s at 20\ifmmode^\circ\else\textdegree\fi{}C. The result is in good agreement with the theoretical prediction, providing an experimental evidence of the difference between them.

Light scattering study of vibrational relaxation in liquids of some heterocyclic compounds

Ultrasonic velocity and absorption were measured in liquid furan (C4H4O), thiophene (C4H4S) and pyridine (C5H5N) over a frequency range from 70 to 700 MHz with high‐resolution Bragg reflection technique [K. Takagi et al., J. Acoust. Soc. Am. 62, 354 (1977)]. The results were described as vibrational relaxation phenomena. In furan and thiophene, all the vibrational modes relax in a single process at 120 and 320 MHz, respectively, at 20 °C. While in pyridine, two relaxation regions were found in a velocity dispersion curve up to 7 GHz, which was obtained in an experiment made cooperatively with Brillouin scattering. Quantitative analysis suggests that all above the third vibrational mode (605 cm−1) relax at 760 MHz, and the lowest (375 cm−1) and the second (405 cm−1) modes, at 3.9 GHz. This type of vibrational double relaxation has already been found in liquid benzene, dichloromethane, and dibromomethane.

Light Scattering Study of Ultrasonic Relaxation in Liquid Furan

A newly developed technique was used to measure the ultrasonic velocity and absorption in liquid furan (C4H4O) at 10°, 20° and 30°C over the range from 60 MHz to 700 MHz. The dispersion observed was about 90 m/s and the decrease in α/f2 was 3500 s2/cm in this range, and they were described with a single relaxation frequency, f''=121 MHz at 20°C. Under an assumption of vibrational relaxation associated with all the modes, the relaxing part of specific heat was calculated theoretically and compared with the experimental value. They were in agreement within 2%, supporting the assumption of the total vibrational relaxation.

Proton spin relaxation and molecular motion in liquid furan

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The polymerization of furan on surfaces

AbstractFuran is a monomer that has but a single conformation and therefore represents a promising candidate for studies of adsorption polymerization with molecules in controlled orientation. It has been adsorbed on a well‐characterized carbon black at known surface concentrations and then polymerized. Spontaneous polymerization occurs to some extent, but irradiation with high‐energy electrons or γ‐rays or the introduction of tin tetrachloride vapors initiates a more complex polymerization.The polymerization of furan in the solid (glassy) state has been accomplished for the first time, using γ‐ray irradiation. As in the case of γ‐ray‐initiated polymerization of liquid furan or adsorbed furan, this polymerization occurs after several hours at room temperature. All the various radiation‐initiated polyfurans that have been studied are rather similar in composition. Molecular weights are low, and infrared absorption occurs in the same regions.Furan vapor polymerizes on the surface of aqueous perchloric acid. This polymer, after isolation from acid‐free water, is slightly cross‐linked and has a high concentration of primary hydroxyl groups. It has the composition expected for a cationically polymerized furan after acid hydrolysis.

Mexico City, Mexico 6–10 November 1966 8th International Congress of Audiology

The ultrasonic absorption in the liquid furan - 2,5-dihydrofuran, furan - 2,3-dihydrofuran and furan - tetrahydrofuran mixtures have been measured in the frequency range from 10 MHz to 2 GHz at temperatures varying from 273 K to 293 K. The method based on the Herzfeld - Litovitz theory for description of experimental data over the frequency and concentration region is proposed. The results of calculations have been interpreted in terms of VV-, VV′- and VT-processes which determine the vibrational kinetics in liquid mixtures. The observed temperature dependence of the kinetic parameters is also discussed. It is shown that proposed method may be used for the estimation of relaxation times of molecules which have a very short vibrational lifetimes.