Solid Condensation Research Articles

An environmentally benign approach for the synthesis of 3,4,5-trisubstituted 2-aminofurans under solvent-free conditions via isocyanide-based multicomponent approach

An efficient solvent-free procedure for the synthesis of 3,4,5-trisubstituted 2-aminofurans has been developed via a multicomponent strategy by the solid state condensation of finely grounded dibenzoylacetylene and aromatic aldehydes in the presence of isocyanides at room temperature. Clean reaction profile, easy work-up procedure, non-chromatographic purification technique, short reaction times, high yields, and solvent-free reaction conditions are the remarkable advantages of this procedure. Single crystal X-ray diffraction has been established for four structures.

Ca–Al-rich inclusions in carbonaceous chondrites: the oldest solar system objects

This paper presents a review of recent available data on the first solid condensates of the Solar System, which include refractory CAIs (Ca–Al-rich Inclusions) mostly composed of Ca, Al, Mg, and Ti minerals. A theoretical condensation sequence calculated from thermodynamic data confirmed that CAIs formed as fine-grained aggregates in the protoplanetary disk from an 16О-rich gas of solar composition at temperatures >1300° K and pressures <10–4 bar. Based on the diversity of CAI types, their mineralogical, bulk chemical, and isotopic compositions, it can be concluded that CAIs experienced melting and evaporation, possibly by shock waves, which may have occurred in the protoplanetary disk within a brief time interval. Some CAIs may have experienced multiple events such as melting, evaporation, and recycling back to the disk by means of a bipolar outflow. The CAIs having an absolute age of 4567.30 ± 0.16 Myr are the oldest objects in the Solar System. The study of CAIs revealed two distinct oxygen isotope reservoirs (16О-rich and 16О-poor) and established a chronology of the sequence of processes forming individual CAI components using Mg–Al, Cr–Mn and Pb–Pb isotopic systematics.

Search for methane isotope fractionation due to Rayleigh distillation on Titan

We search for meridional variation in the abundance of CH3D relative to CH4 on Titan using near-IR spectra obtained with NIRSPAO at Keck, which have a photon-limited signal-to-noise ratio of ∼50. Our observations can rule out a larger than 10% variation in the column of CH3D below 50 km. The preferential condensation of the heavy isotopologues will fractionate methane by reducing CH3D in the remaining vapor, and therefore these observations place limits on the amount of condensation that occurs in the troposphere. While previous estimates of CH3D fractionation on Titan have estimated an upper limit of −6‰, assuming a solid condensate, we consider more recent laboratory data for the equilibrium fractionation over liquid methane, and use a Rayleigh distillation model to calculate fractionation in an ascending parcel of air that is following a moist adiabat. We find that deep, precipitating convection can enhance the fractionation of the remaining methane vapor by −10 to −40‰, depending on the final temperature of the rising parcel. By relating fractionation of our reference parcel model to the pressure level where the moist adiabat achieves the required temperature, we argue that the measured methane fractionation constrains the outflow level for a deep convective event. Observations with a factor of at least 4–6 times larger signal-to-noise are required to detect this amount of fractionation, depending on the altitude range over which the outflow from deep convection occurs.

Peculiarities in the formation of complex organic compounds in a nitrogen–methane atmosphere during hypervelocity impacts

Results of the experiments on model impact vaporization of peridotite, a mineral analogue of stony asteroids, in a nitrogen–methane atmosphere are presented. Nd-glass laser (γ = 1.06 µm) was used for simulation. Pulse energy was ~600–700 J, pulse duration ~10–3 s, vaporization tempereature ~4000–5000 K. The gaseous medium (96% vol. of N2 and 4% vol. of CH4, P = 1 atm) was a possible analogue of early atmospheres of terrestrial planets and corresponded to the present-day atmosphere composition of Titan, a satellite of Saturn. By means of pyrolytic gas chromatography/mass spectrometry, it is shown that solid condensates obtained in laser experiments contain relatively complex lowand high-molecular weight (kerogen-like) organic compounds. The main products of condensate pyrolysis were benzene and alkyl benzenes (including long-chain ones), unbranched aliphatic hydrocarbons, and various nitrogen-containing compounds (aliphatic and aromatic nitriles and pyrrol). It is shown that the nitrogen–methane atmosphere favors the formation of complex organic compounds upon hypervelocity impacts with the participation of stony bodies even with a small methane content in it. In this process, falling bodies may not contain carbon, hydrogen, and other chemical elements necessary for the formation of the organic matter. In such conditions, a noticeable contribution to the impact-induced synthesis of complex organic substances is probably made by heterogeneous catalytic reactions, in particular, Fischer–Tropsch type reactions.

Using the C-O stretch to unravel the nature of hydrogen bonding in low-temperature solid methanol-water condensates.

Transmission infrared spectroscopy has been used in a systematic laboratory study to investigate hydrogen bonding in binary mixtures of CH3OH and H2O, vapour deposited at 30 K, as a function of CH3OH/H2O mixing ratio, R. Strong intermolecular interactions are evident between CH3OH and H2O with infrared band profiles of the binary ices differing from that of the pure components and changing significantly with R. Consistent evidence from the O-H and C-H band profiles and detailed analysis of the C-O stretch band reveal two different hydrogen bonding structural regimes below and above R = 0.6-0.7. The vapour deposited solid mixtures were found to exhibit behaviour similar to that of liquids with evidence of inhomogeneity and higher coordination number of hydrogen bonds that are concentration dependent. The C-O stretch band is found to consist of three components around 1039 cm(-1) ('blue'), 1027 cm(-1) ('middle') and 1011 cm(-1) ('red'). The 'blue' and 'middle' components corresponding to environments with CH3OH dominating as a proton donor (PD) and proton acceptor (PA) respectively reveal preferential bonding of CH3OH as a PA and H2O as a PD in the mixtures. The 'red' component is only present in the presence of H2O and has been assigned to the involvement of both lone pairs of electrons on the oxygen atom of CH3OH as a PA to two PD H2O atoms. Cooperative effects are evident with concurrent blue-shifts in the C-H stretching modes of CH3OH below R = 0.6 indicating CH3 group participation in hydrogen bonding.

Experimental determination and theoretical framework of kinetic fractionation at the water vapour–ice interface at low temperature

Water isotopes are commonly used for climate reconstruction from ice cores. The different heavy isotopes of water such as H218O, H217O or HDO give information about local temperature but also temperature and humidity of water vapour sources. Quantification of these parameters relies on the good knowledge of equilibrium and kinetic isotopic fractionation at each step of the water cycle. One of the strongest limitations when interpreting water isotopes in remote Antarctic ice cores is the formulation of the isotopic fractionation at solid condensation (vapour to ice). This classical formulation also implies a good knowledge of coefficients for equilibrium fractionation and water vapour diffusion in air as well as supersaturation in clouds. The uncertainties associated with these different parameters make the formulation of isotopic fractionation at solid condensation only empirical.Here, we make use (1) of recent development in the measurements of water isotopes in the water vapour through infra-red spectroscopy and (2) of the possibility to measure accurately 17O-excess of water to test the classical formulation and parameterization of isotopic fractionation at solid condensation. A first experiment involving very strong supersaturation evidences a strong kinetic effect on 17O-excess at solid condensation, similar to d-excess. It also shows the limits of the classical formulation of water isotopic fractionation during solid condensation estimation at very low temperature. A second experiment performed in a cloud chamber under controlled conditions uses cavity ring down spectrometers (CRDS) to determine the spatial variability of water vapour isotopic composition due to diffusion (kinetic effect) during solid condensation. The spatial variability of water vapour isotopic composition can be relatively well reproduced by the resolution of diffusion toward a cold plate. This preliminary study opens new perspectives to revisit the classical formulation of water isotopic fractionation during solid condensation at very low temperature.

Condensation versus diffusion. A spatial-scale-independent theory of aggregate structures in edible oils: applications to model systems and commercial shortenings studied via rheology and USAXS

Understanding how solid fats structures come about in edible oils and quantifying their structures is of fundamental importance in developing edible oils with pre-selected characteristics. We considered the great range of fractal dimensions, from 1.91 to 2.90, reported from rheological measurements. We point out that, if the structures arise via DLA/RLA or DLCA/RLCA, as has been established using ultra small angle x-ray scattering (USAXS), we would expect fractal dimensions in the range ~1.7 to 2.1, and ~2.5 or ~3.0. We present new data for commercial fats and show that the fractal dimensions deduced lie outside these values. We have developed a model in which competition between two processes can lead to the range of fractal dimensions observed. The two processes are (i) the rate at which the solid fat particles are created as the temperature is decreased, and (ii) the rate at which these particles diffuse, thereby meeting and forming aggregates. We assumed that aggregation can take place essentially isotropically and we identified two characteristic times: a time characterizing the rate of creation of solid fats, , where is the rate of solid condensation (cm3 s−1), and the diffusion time of solid fats, , where is their diffusion coefficient and is the typical average distance that fats must move in order to aggregate. The intent of this model is to show that a simple process can lead to a wide range of fractal dimensions. We showed that in the limit of very fast solid creation, the fractal dimension is predicted to be that of DLCA, ~1.7, relaxing to that of RLCA, 2.0–2.1, and that in the limit of very slow solid creation, , the fractal dimension is predicted to be that obtained via DLA, ~2.5, relaxing to that of RLA, 3.0. We predict that, given a system which satisfies our model assumptions and which can either be cooled rapidly or cooled slowly to yield fractal dimensions and then . This is supported by both rheological [] and USAXS measurements [, ] even though the latter models do not conform to the assumptions of those presented here.

Microstructural evidence for complex formation histories of amoeboid olivine aggregates from the ALHA77307 CO3.0 chondrite

AbstractThe microstructures and compositions of olivine and refractory components in six amoeboid olivine aggregates (AOAs) in the Allan Hills A77307 CO3.0 chondrite have been characterized in detail using the focused ion beam sample preparation technique with transmission electron microscopy. In the AOAs, refractory components (perovskite, melilite, spinel, anorthite, and Al‐Ti‐bearing diopside) provide evidence of a high degree of textural and compositional heterogeneity, suggesting that these phases have formed by disequilibrium gas–solid condensation at high temperatures under highly dynamic conditions. We infer different possible reactions of early‐condensed solid minerals (perovskite and spinel) with a nebular gas, forming diopside with wide ranges of Al and Ti contents and/or anorthite. The progressive, incomplete consumption of spinel in these reactions may have resulted in the Cr enrichment in the remaining, unreacted spinel in the AOAs. In contrast to the refractory components, olivines in the AOAs have equilibrated textures with 120° triple junctions, indicating that the AOAs were subjected to high‐temperature annealing after agglomeration of olivine and refractory components. Because the AOAs consist of fine‐grained olivine grains with numerous pores, the annealing is constrained by experimental data to have occurred for a short duration of the order of a few hours to tens of hours depending on the annealing temperature. In comparison, the effects of annealing on the refractory components are minimal, probably due to pinning of grain boundaries in the multiphase assemblages that inhibited grain growth.

Origin of native silicon and iron silicides in the Dhofar 280 lunar meteorite

Native silicon and iron silicides were studied in the Dhofar 280 lunar anorthositic meteorite representing an impact-melt breccia. Such rocks are widespread in the highland crust of the Moon. It was established that cryptocrystalline objects containing native silicon are close in composition to the silicon monoxide SiO. Experimental data demonstrate that this compound is the main component of the vapor forming during vaporization of an anorthitic melt. It is suggested that the formation of native silicon was related to the condensation of SiO from an impact-derived vapor cloud. Reducing conditions are determined by the mass-fractionation of silica monoxide and oxygen in the expanding vapor cloud in the gravity field of the Moon. Gaseous SiO may be condensed directly into a solid phase or a mixture of silicon with silica. The condensed SiO phase incorporated into an impact melt should be decomposed into silicon and silica. Interaction of Si, SiO, and SiO2 solid condensates with an impact melt could lead to the observed enrichment of the surrounding liquid in silica. The formation of iron silicides is provided by the reaction of native silicon with FeO presenting in an impact melt. The other iron source could be a meteoritic component, which is identified in silicides by elevated Ni contents. Obtained mineralogical and experimental data show that metallic silicon can be obtained under lunar conditions by distillation of anorthositic melts and can be used for production of solar batteries to provide lunar settlements with energy.

Silicon isotopes in angrites and volatile loss in planetesimals

Inner solar system bodies, including the Earth, Moon, and asteroids, are depleted in volatile elements relative to chondrites. Hypotheses for this volatile element depletion include incomplete condensation from the solar nebula and volatile loss during energetic impacts. These processes are expected to each produce characteristic stable isotope signatures. However, processes of planetary differentiation may also modify the isotopic composition of geochemical reservoirs. Angrites are rare meteorites that crystallized only a few million years after calcium-aluminum-rich inclusions and exhibit extreme depletions in volatile elements relative to chondrites, making them ideal samples with which to study volatile element depletion in the early solar system. Here we present high-precision Si isotope data that show angrites are enriched in the heavy isotopes of Si relative to chondritic meteorites by 50-100 ppm/amu. Silicon is sufficiently volatile such that it may be isotopically fractionated during incomplete condensation or evaporative mass loss, but theoretical calculations and experimental results also predict isotope fractionation under specific conditions of metal-silicate differentiation. We show that the Si isotope composition of angrites cannot be explained by any plausible core formation scenario, but rather reflects isotope fractionation during impact-induced evaporation. Our results indicate planetesimals initially formed from volatile-rich material and were subsequently depleted in volatile elements during accretion.

Isothermal vortex flows in the vicinity of ferro- and diamagnetic condensation cores in magnetic fluids undergoing first-order phase transition

The paper presents the system of analytical equations describing isothermal vortex flows induced in a plane magnetized ferrofluid layer by magnetophoresis of drop-like aggregates. Magnetophoresis of the aggregates is caused by configuration of a constant inhomogeneous magnetic field in the vicinity of a solid condensation core placed in the fluid. The vortex flow generated by inhomogeneous ponderomotive force drives the aggregates into the region of highest magnetic field intensity, which resembles condensation of drops at the surface of the core. The dynamic equations are written for the case of dilute magnetic fluids and take into account the dynamics of the drop-like aggregate growth. Numerical simulation based on the proposed system of equations is in qualitative agreement with the experimental data obtained in the Hele-Shaw cell.

Morphology-Controlled Preparation of Heteropolyanion-Derived Mesoporous Solid Base

Heteropolyanion-derived mesoporous solid base catalysts were prepared by designing the basic ionic liquid (IL) N-3-[2-(2-aminoethylamino)ethylamino]-2-hydroxypropyl)pyridinium chloride ([TAHpy]Cl) to assemble with Keggin-structured sodium phosphotungstate (Na3PW12O40) in the aqueous solution containing organic base diethylenetriamine (DETA). The obtained hybrids were characterized by various techniques such as thermogravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscope, and nitrogen adsorption experiments. In the synthesis, the concentration of DETA was adjusted to control the morphology and mesostructure of the obtained basic hybrids, and concentrated DETA caused the formation of the mesoporous solid base. The structure analysis indicated that the obtained hybrid demonstrated a piece-like shape in macroscopical size, and these species were assembled by relative uniform small nanoellipsoids with the diameter of ∼50 nm, which forms a loosely packed structure. Assessed in the liquid–solid heterogeneous Knoevenagel condensation, the mesoporous solid base with a morphology of loosely packed nanoparticles presented superior activity, which was about 14 times higher than the nonporous analogues with large block morphology. A possible catalytic mechanism is proposed to explain the efficient catalytic performance.

Amoeboid olivine aggregates from CH carbonaceous chondrites

Amoeboid olivine aggregates (AOAs) in CH carbonaceous chondrites are texturally and mineralogically similar to those in other carbonaceous chondrite groups. They show no evidence for alteration and thermal metamorphism in an asteroidal setting and consist of nearly pure forsterite (Fa<3; in wt%, CaO=0.1–0.8, Cr2O3=0.04–0.48; MnO<0.5), anorthite, Al-diopside (in wt%, Al2O3=0.7–8.1; TiO2<1), Fe,Ni-metal, spinel, and, occasionally, low-Ca pyroxene (Fs1Wo2–3), and calcium–aluminum-rich inclusions (CAIs). The CAIs inside AOAs are composed of hibonite, grossite, melilite (Åk13–44), spinel, perovskite, Al,Ti-diopside (in wt%, Al2O3 up to 19.6; TiO2 up to 13.9), and anorthite. The CH AOAs, including CAIs within AOAs, have isotopically uniform 16O-rich compositions (average Δ17O=−23.4±2.3‰, 2SD) and on a three-isotope oxygen diagram plot along ∼slope-1 line. The only exception is a low-Ca pyroxene-bearing AOA 1-103 that shows a range of Δ17O values, from −24‰ to −13‰. Melilite, grossite, and hibonite in four CAIs within AOAs show no evidence for radiogenic 26Mg excess (δ26Mg). In contrast, anorthite in five out of six AOAs measured has δ26Mg corresponding to the inferred initial 26Al/27Al ratio of (4.3±0.7)×10−5, (4.2±0.6)×10−5, (4.0±0.3)×10−5, (1.7±0.2)×10−5, and (3.0±2.6)×10−6. Anorthite in another AOA shows no resolvable δ26Mg excess; an upper limit on the initial 26Al/27Al ratio is 5×10−6. We infer that CH AOAs formed by gas–solid condensation and aggregation of the solar nebula condensates (forsterite and Fe,Ni-metal) mixed with the previously formed CAIs. Subsequently they experienced thermal annealing and possibly melting to a small degree in a 16O-rich gaseous reservoir during a brief epoch of CAI formation. The low-Ca pyroxene-bearing AOA 1-103 may have experienced incomplete melting and isotope exchange in an 16O-poor gaseous reservoir. The lack of resolvable δ26Mg excess in melilite, grossite, and hibonite in CAIs within AOAs reflects heterogeneous distribution of 26Al in the solar nebula during this epoch. The observed variations of the inferred initial 26Al/27Al ratios in anorthite of the mineralogically pristine and uniformly 16O-rich CH AOAs could have recorded (i) admixing of 26Al in the protoplanetary disk during the earliest stages of its evolution and/or (ii) closed-system Mg-isotope exchange between anorthite and Mg-rich minerals (spinel, forsterite, and Al-diopside) during subsequent prolonged (days-to-weeks) thermal annealing at high temperature (∼1100°C) and slow cooling rates (∼0.01Kh−1) that has not affected their O-isotope systematics. The proposed thermal annealing may have occurred in an impact-generated plume invoked for the origin of non-porphyritic magnesian chondrules and Fe,Ni-metal grains in CH and CB carbonaceous chondrites about 5Myr after formation of CV CAIs.

Highly siderophile elements in Earth’s mantle as a clock for the Moon-forming impact

According to the generally accepted scenario, the last giant impact on Earth formed the Moon and initiated the final phase of core formation by melting Earth's mantle. A key goal of geochemistry is to date this event, but different ages have been proposed. Some argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others claim a date later than 50 Myr (and possibly as late as around 100 Myr) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9 per cent confidence level. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on an Earth-like planet and the amount of mass subsequently added during the era known as Late Accretion. As the last giant impact is delayed, the late-accreted mass decreases in a predictable fashion. This relationship exists within both the classical scenario and the Grand Tack scenario of terrestrial planet formation, and holds across a wide range of disk conditions. The concentration of highly siderophile elements (HSEs) in Earth's mantle constrains the mass of chondritic material added to Earth during Late Accretion. Using HSE abundance measurements, we determine a Moon-formation age of 95 ± 32 Myr after condensation. The possibility exists that some late projectiles were differentiated and left an incomplete HSE record in Earth's mantle. Even in this case, various isotopic constraints strongly suggest that the late-accreted mass did not exceed 1 per cent of Earth's mass, and so the HSE clock still robustly limits the timing of the Moon-forming event to significantly later than 40 Myr after condensation.

On the computation of moist‐air specific thermal enthalpy

The specific thermal enthalpy of a moist‐air parcel is defined analytically following a method in which specific moist entropy is derived from the Third Law of Thermodynamics. Specific thermal enthalpy is computed by integrating specific heat content with respect to absolute temperature and including the impacts of various latent heats (i.e. solid condensation, sublimation, melting, and evaporation). It is assumed that thermal enthalpies can be set to zero at 0 K for the solid form of the main chemically inactive components of the atmosphere (solid‐α oxygen and nitrogen, hexagonal ice). The moist thermal enthalpy is compared to already existing formulations of moist static energy (MSE). It is shown that the differences between thermal enthalpy and the thermal part of MSE may be quite large. This prevents the use of MSE for evaluating accurately the enthalpy budget of a moist atmosphere, a situation that is particularly true when dry air and cloud parcels mix because of entrainment/detrainment processes along the edges of cloud. Other differences are observed when MSE or moist‐air thermal enthalpy is plotted on a psychrometric diagram or when vertical profiles of surface deficit are plotted.

Fabrication and characterization of hexagonally patterned quasi-1D ZnO nanowire arrays

Quasi-one-dimensional (quasi-1D) ZnO nanowire arrays with hexagonal pattern have been successfully synthesized via the vapor transport process without any metal catalyst. By utilizing polystyrene microsphere self-assembled monolayer, sol–gel-derived ZnO thin films were used as the periodic nucleation sites for the growth of ZnO nanowires. High-quality quasi-1D ZnO nanowires were grown from nucleation sites, and the original hexagonal periodicity is well-preserved. According to the experimental results, the vapor transport solid condensation mechanism was proposed, in which the sol–gel-derived ZnO film acting as a seed layer for nucleation. This simple method provides a favorable way to form quasi-1D ZnO nanostructures applicable to diverse fields such as two-dimensional photonic crystal, nanolaser, sensor arrays, and other optoelectronic devices.

Physical adsorption characterization of nanoporous materials: progress and challenges

Within the last two decades major progress has been achieved in understanding the adsorption and phase behavior of fluids in ordered nanoporous materials and in the development of advanced approaches based on statistical mechanics such as molecular simulation and density functional theory (DFT) of inhomogeneous fluids. This progress, coupled with the availability of high resolution experimental procedures for the adsorption of various subcritical fluids, has led to advances in the structural characterization by physical adsorption. It was demonstrated that the application of DFT based methods on high resolution experimental adsorption isotherms provides a much more accurate and comprehensive pore size analysis compared to classical, macroscopic methods. This article discusses important aspects of major underlying mechanisms associated with adsorption, pore condensation and hysteresis behavior in nanoporous solids. We discuss selected examples of state-of-the-art pore size characterization and also reflect briefly on the existing challenges in physical adsorption characterization.

Synthesis, experimental, and DFT studies on FT-IR, 1H, and 13C NMR spectra of azo-linked dihydropyridines

An efficient one-pot synthesis of dihydropyridines by solid state three-component condensation reactions of aldehydes, dimedone, and ammonium acetate in the presence of HY-Zeolite has been achieved. The conversion took short time to form the products in excellent yields. HY-Zeolite can be recovered and reused. Density Functional Theory (DFT) calculations at the B3LYP level is used to optimize the geometry and calculate FT-IR, 1H, and 13C NMR spectra of the compounds. We found that the calculated values are in accordance with the experimental data.

High molecular weight poly(ethylene-2,5-furanoate); critical aspects in synthesis and mechanical property determination

Furan-2,5-dicarboxylic acid (FDCA) is a widely advocated renewable substitute for terephthalic acid (TA). Preparation of high molecular weight FDCA based polyesters by an industrially common combination of melt polymerization and subsequent solid state post condensation is described. Ultimately, poly(ethylene 2,5-furanoate) (PEF) with absolute Mn = 83,000 g mol−1 is obtained, determined by triple detection Size Exclusion Chromatography. The bulk polymer properties of FDCA based polyesters, necessary to evaluate their industrial potential were determined the Young's modulus of PEF is determined to be 2450 ± 220 MPa and the maximum stress 35 ± 8 MPa. The influence of crystallinity on the mechanical properties as function of temperature was determined by dynamic mechanical thermal analysis. A detailed differential scanning calorimetry study on the crystallization behavior of high molecular weight PEF allowed to calculate the equilibrium melting temperature (Tm0) of 239.3 and 239.7 °C for the first and second melting peak, respectively. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4191–4199

Alteration and multi-stage accumulation of oil and gas in the Ordovician of the Tabei Uplift, Tarim Basin, NW China: Implications for genetic origin of the diverse hydrocarbons

The Ordovician is the most important exploration target in the Tabei Uplift of the Tarim Basin, which contains a range of petroleum types including solid bitumen, heavy oil, light oil, condensate, wet gas and dry gas. The density of the black oils ranges from 0.81 g/cm3 to 1.01 g/cm3 (20 °C) and gas oil ratio (GOR) ranges from 4 m3/m3 to 9300 m3/m3. Oil-source correlations established that most of the oils were derived from the Mid-Upper Ordovician marine shale and carbonate and that the difference in oil properties is mainly attributed to hydrocarbon alteration and multi-stage accumulation. In the Tabei Uplift, there were three main periods of hydrocarbon accumulation in the late Caledonian stage (ca. 450–430 Ma), late Hercynian stage (ca. 293–255 Ma) and the late Himalayan stage (ca. 12–2 Ma). The oil charging events mainly occurred in the late Caledonian and late Hercynian stage, while gas charging occurred in the late Hercynian stage. During the late Caledonian stage, petroleum charged the reservoirs lying east of the uplift. However, due to a crustal uplifting episode in the early Hercynian (ca. 386–372 Ma), most of the hydrocarbons were transformed by processes such as biodegradation, resulting in residual solid bitumen in the fractures of the reservoirs. During the late Hercynian Stage, a major episode of oil charging into Ordovician reservoirs took place. Subsequent crustal uplift and severe alteration by biodegradation in the west-central Basin resulted in heavy oil formation. Since the late Himalayan stage when rapid subsidence of the crust occurred, the oil residing in reservoirs was exposed to high temperature cracking conditions resulting in the production of gas and charged from the southeast further altering the pre-existing oils in the eastern reservoirs. A suite of representative samples of various crude oils including condensates, lights oils and heavy oils have been collected for detailed analysis to investigate the mechanism of formation. Based on the research it was concluded that the diversity of hydrocarbon physical and chemical properties in the Tabei Uplift was mainly attributable to the processes of biodegradation and gas washing. The understanding of the processes is very helpful to predict the spatial distribution of hydrocarbon in the Tabei Uplift and provides a reference case study for other areas.