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Experiments show variety of polyimidazoles prepared by aromatic nucleophilic displacement, from reactions of bisphenol imidazoles with activated difluoro compounds. Polyimidazoles have good mechanical properties making them suitable for use as films, moldings, and adhesives.
The highly variegated surface of Pluto revealed by the New Horizons spacecraft is composed of both volatile ices (N2, CH4, CO) and H2O ice, all of which are intrinsically colorless. The colors on Pluto reveal a non-ice component generally acknowledged to be a refractory complex organic material (tholins) produced by photolysis in the planet’s atmosphere [1], and by photolysis and radiolysis of the surface ices [2-4]. These processes have produced a range of colors from pale yellow to red to brown, and result in a variation of a factor of 10in albedo across the surface. Tholins are disordered polymer-like materials made of repeating chains of linked subunits and complex combinations of functional groups containing carbon. Nitrogen, oxygen, and other elements can be substituted in both the aliphatic and aromatic subunits. The detection of the spectral absorption of an ammoniated compound associated with surface exposures of red-colored H2O ice (herein, RAW) in the LEISA spectral mapping data from New Horizons suggests that a third source of a colored material is ejected from Pluto’s interior as a water-rich fluid(cryomagma) that rapidly freezes at the low temperature (~40K) of the surface [5,6]. The ammoniated compound is thought to be an ammonia hydrate or an ammoniated salt; the spectral data cover a limited wavelength range, resulting in ambiguity in the identification of the form of the ammonia. The distribution of RAW in the vicinity of tectonically stressed and deformed geological structures, particularly graben (fossae), is seen as the result of both fluid effusion and fountaining ejection of cryoclastic materials in Pluto’s Virgil Fossae region [5,6]. RAW is seen elsewhere on Pluto, both in association with graben complexes and on broad expanses of old surface, but primarily in zones of tectonic stress. The nature of the putative subsurface fluid is unknown, but it must have existed at relatively shallow depths such that the graben faulting could reach it. Geochemical modeling of fluids in the interiors of small planetary bodies in the outer Solar System[7] shows that ammonia-bearing H2O in contact with rock and metal components produce a rich chemical soup, including gases that can, in principle, help propel the fluid from shallow reservoirs through crustal fractures to reach the surface. An organic component of the fluid cryomagma is predicted to originate from thermal processing of the components [ref] and may be an example of one-pot synthesis of such complexes as amino acid precursors [ref].
As a theoretical component of the joint effort with the laboratory of Dr. Lou Allamandola to search for potential candidates for interstellar organic carbon compound that are responsible for the visible diffuse interstellar absorption bands (DIB's), quantum mechanical calculations were performed on the electron absorption spectra of selected polycyclic aromatic hydrocarbons (PAH) and derivatives. In the completed project, 15 different species of naphthalene, its hydrogen abstraction and addition derivatives, and corresponding cations and anions were studied. Using semiempirical quantum mechanical method INDO/S, the ground electronic state of each species was evaluated with restricted Hartree-Fock scheme and limited configuration interaction. The lowest energy spin state for each species was used for electron absorption calculations. Results indicate that these calculations are accurate enough to reproduce the spectra of naphthalene cation and anion observed in neon matrix. The spectral pattern of the hydrogen abstraction and addition derivatives predicted based on these results indicate that the electron configuration of the pi orbitals of these species is the dominant determinant. A combined list of 19 absorptions calculated from 4500 A to 10,400 A were compiled and suggested as potential candidates that are relevant for the DIB's absorptions. Continued studies on pyrene and derivatives revealed the ground state symmetries and multiplicities of its neutral, anionic, and cationic species. Spectral calculations show that the cation (B(sub 3g)-2) and the anion (A(sub u)-2) are more likely to have low energy absorptions in the regions between 10 kK and 20 kK, similar to naphthalene. These absorptions, together with those to be determined from the hydrogen abstraction and addition derivatives of pyrene, can be used to provide additional candidates and suggest experimental work in the search for interstellar compounds that are responsible for DIB's.
Stable isotope ratio measurements of carbon atoms using isotope ratio mass spectrometry (IRMS) can be an effective tool for quantifying biogenic carbon in co-processed fuels, with results approaching the precision and accuracy of accelerator mass spectrometry (AMS). The lower cost of an IRMS may enable deployment to refineries, improving access and analysis turnaround times (≤2 hours), and, by extension, provide data that can allow process optimization to maximize renewable carbon in desired refinery products. This project explored the integration of chemical separation with IRMS analyses to enable highly detailed tracking of biogenic carbon into fuel product streams separated by boiling point range, chemical class, or specific compound. Forty-nine fuels and fuel components of fossil and biogenic origin, spanning gasoline and diesel boiling point ranges, were received from three refiners and were analyzed for their δ 13 C values via IRMS. Results spanned a 13 C range from ca. 10‰ to 44‰ and reflect materials derived from sustainable sources (e.g., C4 or C3 plants, animal-based pathways, syngas) or from fossil-derived fuels. Common ranges are approximately 18‰ to 9‰ and approximately 30‰ to 20‰ for C4 and C3 plants, respectively, and approximately 34‰ to 24‰ and approximately 70‰ to 33‰ for petroleum-derived fuels and methane, respectively. Fuel-like standards were developed and tested using direct-injection elemental analyzer (EA) IRMS for liquid fuels. This method was compared with the published methods, yielding statistically similar results. Four blend curve sets were produced ranging from 0% to 100% of a fuel containing biogenic carbon, focusing on 0% to 10% biogenic carbon. Linear fits were the most applicable for two of the four blend curve sets; however, two sets were found to exhibit slightly quadratic behavior, which was more pronounced in low biogenic blend samples, necessitating second-order fits. The origin of the slight quadratic behavior remains unclear; however, the discussion points to possible interpretations. CanmetENERGY thoroughly characterized a majority of the samples using one- and two-dimensional gas chromatography (GC and GC×GC, respectively) and other analyses. Selected samples were subjected to solid phase extraction (SPE) for saturate, olefin, aromatic, and polar (SOAP) analysis, and the resulting solvent-diluted fractions containing saturates and aromatics were returned to Pacific Northwest National Laboratory (PNNL), where the solvent was removed via evaporation or physical separation using GC techniques. Characterization and separations provided an understanding of saturate and aromatic content, as well as boiling point ranges for each sample and sample fraction. Samples resulting from SPE were examined using EA-IRMS and gas chromatography combustion IRMS (GC-C-IRMS) analyses. Both approaches suggest that the range in values between end-members can be increased by selecting the paraffinic or aromatic fraction of the end-member or by selecting among individual compounds resulting from GC separation of the paraffinic fractions. Considerable work remains to put these approaches into practice and statistically validate the benefit for using a fraction or individual compound over bulk analysis of a sample. However, initial results suggest that separations provide advantages for samples having blend ratios of less than 10% biogenic blendstocks. 13 C results showed statistically similar biofuel blend results to those obtained at PNNL, although additional work is needed to obtain better reproducibility. Select samples were sent to Los Alamos National Laboratory (LANL) for IRMS measurements and Beta Analytics for AMS measurements. This work suggests that IRMS and AMS yield closely comparable results and in some circumstances, IRMS could serve as a surrogate for AMS. While additional work is needed to better resolve statistical advantages for separations and better show the comparable nature of IRMS and AMS in both the biogenic carbon analysis of bulk chemical classes, initial results from this study suggest that these should be pursued in order to proliferate this approach for quantifying biogenic carbon in transportation fuels to the refinery level, thereby potentially enabling process optimization in co-processing scenarios.
The formation of fatty acids by Fischer-Tropsch-type synthesis was investigated with ferric oxide, ammonium carbonate, potassium carbonate, powdered Pueblito de Allende carbonaceous chondrite, and filings from the Canyon Diablo meteorite used as catalysts. Products were separated and identified by gas chromatography and mass spectrometry. Iron oxide, Pueblito de Allende chondrite, and Canyon Diablo filings in an oxidized catalyst form yielded no fatty acids. Canyon Diablo filings heated overnight at 500 C while undergoing slow purging by deuterium produced fatty acids only when potassium carbonate was admixed; potassium carbonate alone also produced these compounds. The active catalytic combinations gave relatively high yields of aliphatic and aromatic hydrocarbons; substantial amounts of n-alkenes were almost invariably observed when fatty acids were produced; the latter were in the range C6 to C18, with maximum yield in C9 or 10.
The Murchison meteorite contains aliphatic and aromatic hydrocarbons similar to those made in static Fischer-Tropsch-type syntheses. Principal compound classes above C8 are n-alkanes, mono- and dimethylalkanes, alkenes, alkylbenzenes and -naphthalenes. Below C8, n-alkanes are virtually absent; instead, benzene, toluene, branched alkanes dominate. The CH4/C2H6 ratio is greater than 30, possibly greater than 700. Isoprenoids from C17 to C20 occur in a surface rinse but not in subsequent extracts and appear to be terrestrial contaminants. Thiophenes, porphyrin-like pigments, and chlorobenzenes were also found; the latter appear to be contaminants. In the Allende meteorite, only methane, benzene, toluene and an aromatic polymer seem to be indigeneous. A comprehensive review of current evidence shows that Fischer-Tropsch-type reactions can account for most principal features of meteorite organic matter.
Organic compounds carbon K emission spectra, using light element X ray spectrometer for aliphatic, aromatic and partly ionic substances spectral analysis
A dark reddish organic solid, called tholin, is synthesized from simulated Titanian atmospheres by irradiation with high energy electrons in a plasma discharge. The visible reflection spectrum of this tholin is found to be similar to that of high altitude aerosols responsible for the albedo and reddish color of Titan. The real (n) and imaginary (k) parts of the complex refractive index of thin films of Titan prepared by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mb is determined from X-ray to microwave frequencies. Values of n (approx. 1.65) and k (approx. 0.004 to 0.08) in the visible are consistent with deductions made by groundbased and spaceborne observations of Titan. Many infrared absorption features are present in k(lambda), including the 4.6 micrometer nitrile band. Molecular analysis of the volatile components of this tholin was performed by sequential and nonsequential pyrolytic gas chromatography/mass spectrometry. More than one hundred organic compounds are released; tentative identifications include saturated and unsaturated aliphatic hydrocarbons, substituted polycylic aromatics, nitriles, amines, pyrroles, pyrazines, pyridines, pyrimidines, and the purine, adenine. In addition,acid hydrolysis produces a racemic mixture of biological and nonbiological amino acids. Many of these molecules are implicated in the origin of life on Earth, suggesting Titan as a contemporary laboratory environment for prebiological organic chemistry on a planetary scale.
The results of a NACA investigation conducted over a period of several years to evaluate the anti-knock characteristics of organic compounds are summarized. Included are data for 18 branched paraffins and olefins, 27 aromatics, and 22 ethers. The factors of performance investigated were blending characteristics, temperature sensitivity, lead response, and relation between molecular structure and antiknock ratings. Four engines were used.
Astrochemistry laboratory experiments recently showed that molecules of prebiotic interest can potentially form in space, as supported by the detection of amino acids in organic residues formed by the UV photolysis of ices simulating interstellar and cometary environments (H2O, CO, CO2, CH3OH, NH3, etc.). Although the presence of amino acids in the interstellar medium (ISM) is still under debate, experiments and the detection of amino acids in meteorites both support a scenario in which prebiotic molecules could be of extraterrestrial origin, before they are delivered to planets by comets, asteroids, and interplanetary dust particles. Nucleobases, the informational subunits of DNA and RNA, have also been detected in meteorites, although they have not yet been observed in the ISM. Thus, these molecules constitute another family of prebiotic compounds that can possibly form via abiotical processes in astrophysical environments. Nucleobases are nitrogen-bearing cyclic aromatic species with various functional groups attached, which are divided into two classes: pyrimidines (uracil, cytosine, and thymine) and purines (adenine and guanine). In this work, we study how UV irradiation affects pyrimidine mixed in interstellar ice analogs (H2O, NH3, CH3OH). In particular, we show that the UV irradiation of H2O:pyrimidine mixtures leads to the production of oxidized compounds including uracil, and show that both uracil and cytosine are formed upon irradiation of H2O:NH3:pyrimidine mixtures. We also study the photostability of pyrimidine and its photoproducts formed during these experiments.
Styrene is an important compound for polymer production and a key intermediate in gas-phase kinetics of polycyclic aromatic hydrocarbons (PAHs). For the first time, the pyrolysis of styrene with and without the presence of acetylene is investigated in a single-pulse shock tube coupled to gas chromatography and mass spectrometry. For each reaction system, quantitative speciation profiles are probed within the temperature range of 1100-1730 K, nominal pressure of 20 bar, and reaction duration of similar to 4 ms. A kinetic model is built to simulate the results. The model explains how styrene is consumed under high-pressure pyrolytic conditions, how the secondary chemistry of intermediate products affect subsequent PAH formation, and how acetylene addition alters the reaction pathways. Throughout the temperature range, styrene breakdown is dominated by the bimolecular interaction between styrene and hydrogen atom, which produces benzene+vinyl or phenyl and ethylene through the stabilization of 2-phenylethyl and its subsequent dissociation. As a result, large amounts of phenyl accumulate, which react with styrene to form C14H12 species while simultaneously releasing H atoms through addition/elimination reactions. The reactivity of fuel consumption is preserved by the regeneration of H atoms as chain carriers. Several C14H10 compounds are formed as a result of the following breakdown of the C14H12 isomers, particularly stilbene, 1,1-diphenyl ethylene, and 9-methyl-9H-fluorene. The presence of acetylene as a co-reactant with styrene allows the Hydrogen-Abstraction-Acetylene-Addition (HACA) pathway to proceed from phenyl radical to enhance the production of phenylacetylene at very low temperatures and acenaphthylene. This hinders the formation of C14H12 isomers, exclusive products from pure styrene dissociation by competing with the styrene+phenyl routes.
In recent years, polycyclic aromatic nitrogen heterocycles (PANHs) have attracted a good deal of attention because of their potent carcinogenic and mutagenic properties, and their prevalence in our environment. Such species also play a prominent role in the chemistry of life up to and including the very nucleobases from which our DNA is constructed. Surprisingly, these compounds may even be common outside of our terrestrial environment. To wit, it is now widely accepted that polycyclic aromatic materials are abundant in space and represent a major reservoir of organic carbon in the interstellar medium and developing planetary systems. Given that nitrogen is the fourth most abundant chemically reactive element in space (surpassed only by hydrogen, carbon, and oxygen), it is entirely reasonable to suspect that PANHs may represent an important component of that organic reservoir. Motivated by their intrinsic merit and with special attention toward evaluating their exobiological significance, we have initiated a program to study the spectroscopic and chemical properties of P A " s under conditions relevant to extraterrestrial environments. Here we present the first results of that program-infrared spectroscopic measurements on a series of PANH"s in neutral and cationic forms, isolated in inert matrices at cryogenic temperatures.temperatures. The species studied include: 1 -, and 2-azabenz[a]anthracene, 1-, 2-, and 4- azachrysene, dibenz[a,h]acridine, and dibenz[a,J)acridine. The experimental measurements are also compared with theoretical spectra calculated using density functional theory. General spectroscopic trends observed in this series of compounds are discussed and the implications of these results for Astrophysics and Exobiology are considered.
The Perseverance rover landed in Jezero crater, a site selected to fulfill the Mars-2020 mission goals of characterizing the geology of habitable environments and searching for signs of life while collecting samples for return to Earth [1]. Jezero hosted an open-basin lake during the late Noachian/early Hesperian (~3.7 Ga) [1-2], has units associated with the largest carbonate deposit identified on Mars [3-4], and has a well-preserved delta with clay and carbonate-bearing sediments, well-suited to preservation of organics [1,3-4]. Investigating the nature of organics and aqueous environments within their geologic con-text allows us to understand important aqueous processes and determine habitability within Jezero crater. Previous in situ landed measurements of organics could not resolve their spatial and mineralogical con-text [5-6]. Although Martian meteorites lack geological context, the spatial distribution of organic compounds in Martian meteorites have allowed recognition of an association between aqueous processes and organics [7-8]. Here, we show for the first time in-situ associations between carbonate-forming ultramafic alteration process, later stage aqueous sulfate and perchlorate formation, and organics on the Martian surface. Methodology and geological context: We use the Perseverance rover’s SHERLOC instrument (Scanning Habitable Environments with Raman and Lumines-ence of Organics and Chemicals), a deep-ultraviolet fluorescence and Raman scattering spectrometer capable of mapping the organic and mineral composition with a spatial resolution of 100 μm resolution to report the presence of organics and aqueously formed minerals at Jezero crater [9]. These spectral detections were compared with co-located images obtained with the autofocus context imager (ACI) and the WATSON camera for textural analysis [9]. As of writing, the Per-severance rover has abraded five targets that were measured with the SHERLOC instrument. The five targets are located in two different orbitally-identified geological units within the floor of Jezero crater; the Crater Floor Fractured Rough unit (CF-Fr) and the Séítah region within the Crater Floor Fractured 1 unit (CF-F1) [10]. In orbital infrared spectroscopic data, the CF-Fr unit is associated with pyroxene spectral signatures and minor alteration, while the Séítah region is associated with olivine and minor Mg-rich carbonates and clays [3-4,10]. Carbonation of ultramafic protolith recorded within Jezero crater: All scans of abraded targets within the Séítah region reveal strong peaks at 1080–1090 cm−1 consistent with carbonate and peak singlets or doublets at 820–840 cm−1 attributed to olivine (Fig. 1), consistent with orbital infrared observations. Our detailed micron-scale petrographic and spectroscopic evidence shows that these carbonates formed through carbonation of an ultramafic protolith. The supporting observations include: (1) Carbonate cation compositions match those of olivine, suggesting mixed Fe- and Mg-olivine gave rise to mixed Fe- and Mg-carbonates, similar to observations of ultramafic systems on Earth and within Martian meteorites [3-4,7-8]. (2) The ob-served carbonates co-occur with hydrated materials, gypsum, and potentially aqueously-formed phases, amorphous silicates and phosphate. (3) The spectral and textural variation of olivine and carbonate dominated zones and olivine-carbonate mixtures within both primary grains and interstitial zones are expected for carbonated ultramafic protoliths. (4) These mineral associations and textures closely resemble those observed within the ALH84001 and Nakhlite meteorites attributed to olivine carbonation on Mars [6-7]. Taken together, micron-scale SHERLOC documentation of these phenomena bridge previous orbital and meteorite observations and demonstrate in-situ regionally extensive (~106 km2) ultramafic alteration resulting in geo-logical deposition of carbonates. Furthermore, we observe that olivine carbonation was involved in preserving and possibly synthesizing organics, which makes this environment potentially habitable, as previously suggested in [1,3-4] (Fig. 1). Late-stage aqueous perchlorate and sulfate in Jezero crater: An abrasion target within the CF-Fr unit contains combinations of high intensity 950-955 cm−1 peaks and minor 1090-1095 cm−1 and 1150-1155 cm−1 peaks that are spectral fits to anhydrous perchlorate (Fig. 1). Some spectra show a combination of 950-955 cm−1 peaks with equally strong 1010-1020 cm−1 peaks, low intensity broad features at 1120 cm−1, and occasional broad 3450 cm−1 hydration (-OH) features, indicating a mixture of Ca-sulfate and perchlorate that is minimally hydrated (Fig. 1). The detections of per-chlorates within Jezero crater differ from previous measurements (e.g. Phoenix lander, Curiosity rover, Tissint meteorite [7,11]) because they are observed to be intimately related to aqueous processes including sulfate formation, they present as a secondary white void-fill occurring within the interior of the rock, and they are found to likely be Na-perchlorate. implications for their formation: Three different types of organics embedded within three different lithologies were observed within the abraded targets. Organics associated with low intensity ~340 nm fluorescence were widespread within targets with no apparent association to particular minerals (Fig. 1). Organics associated with ~305 nm and ~275 nm fluorescence correlated with sulfates within the Bellegarde target in the CF-Fr unit, while organics associated with high intensity ~340 nm fluorescence correlated with carbonate, phosphate, and amorphous silicate mixtures within the Garde target in the Séítah region (Fig. 1). Although assignment of fluorescence signatures to specific organic compounds is not conclusive, ~340 nm fluorescence is generally more consistent with 2-ring aromatic organics, ~275 nm fluorescence is more consistent with 1-ring aromatic organics, and ~305 nm fluorescence can be created by either 2- or 1-ring aromatics [12]. These observations indicate that the strongest fluorescence signatures interpreted as organics were found in materials associated with aqueous processes, i.e. sulfate- and carbonate-bearing materials, suggesting both brines and ultramafic carbonation aqueous environments were capable of preserving organics on ancient Mars. In Martian meteorites, simple aromatic organics proposed to have been synthesized through aqueous processes can be found within minerals associated with olivine carbonation and in spatial association with perchlorate and sulfate materials [7-8], similar to SHERLOC observations. Hence, we advance an abiotic aqueous synthesis origin for the organics although we cannot rule out the presence of organics from meteoritic in-fall or putative organic biosignatures. Detailed analyses will be required upon return of these materials to Earth.
The sample from the near-Earth carbonaceous asteroid (162173) Ryugu is analyzed in the context of carbonaceous meteorites soluble organic matter. The analysis of soluble molecules of samples collected by the Hayabusa2 spacecraft shines light on an extremely high molecular diversity on the C-type asteroid. Sequential solvent extracts of increasing polarity of Ryugu samples are analyzed using mass spectrometry with complementary ionization methods and structural information confirmed by nuclear magnetic resonance spectroscopy. Here we show a continuum in the molecular size and polarity, and no organomagnesium molecules are detected, reflecting a low temperature and water-rich environment on the parent body approving earlier mineralogical and chemical data. High abundance of sulfidic and nitrogen rich compounds as well as high abundance of ammonium ions confirm the water processing. Polycyclic aromatic hydrocarbons are also detected in a structural continuum of carbon saturations and oxidations, implying multiple origins of the observed organic complexity, thus involving generic processes such as earlier carbonization and serpentinization with successive low temperature aqueous alteration.
The primary objective is to prepare high temperature polymeric materials, especially linear aromatic polyimides, which maintain their integrity and toughness during long exposure times at elevated temperatures. The attained benefits are obtained by first providing the bis (exocyclodiene) bis (4-(3,4-dimethylene-pyrrolidyl)-phenyl) methane, which is a novel material formed from the monomer N-phenyl-3,4-dimethylene-pyrrolidine. This compound undergoes Diels-Alder reaction with a bismaleimide, without the evolution of gaseous by-products, to form the aromatic polyimide bis (4-(3,4-dimethylene-pyrrolidyl)-phenyl) methane.
Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. ID We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with LTV light from a hydrogen plasma lamp: The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.
Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.
Herbig's (1970) hypothesis that solar nebulae might be the principal source of interstellar grains and molecules is investigated. The investigation includes the determination of physical and chemical conditions in the early solar system. The production of organic compounds in the solar nebula is studied, and the compounds in meteorites are compared with those obtained in Miller-Urey and Fischer-Tropsch-type (FTT) reactions, taking into consideration aliphatic hydrocarbons, aromatic hydrocarbons, purines, pyrimidines, amino acids, porphyrins, and aspects of carbon-isotope fractionation. It is found that FTT reactions account reasonably well for all well-established features of organic matter in meteorites investigated. The distribution of compounds produced by FTT reactions is compared with the distribution of interstellar molecules. Biological implications of the results are considered.