Imperial College London

DrWrenMontgomery

Faculty of EngineeringDepartment of Earth Science & Engineering

Honorary Research Associate
 
 
 
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Contact

 

+44 (0)20 7594 5185w.montgomery CV

 
 
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Location

 

440/33Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

35 results found

Potiszil C, Montgomery W, Sephton M, 2021, Heterogeneity within refractory organic matter from CM2 carbonaceous chondrites: evidence from Raman spectroscopy, Earth and Planetary Science Letters, ISSN: 0012-821X

CM2 chondrites experienced widespread aqueous and short term thermal alteration on their parent bodies. Whilst previous Raman spectroscopic investigations have investigated insoluble organic matter (IOM), they have not taken into account the binary nature of IOM. Studies employing mass spectrometry have indicated that IOM also known as macromolecular organic matter (MOM) is in fact composed of two distinct fractions: labile organic matter (LOM) and refractory organic matter (ROM). The ROM component represents the aromatic rich and heteroatom poor component of IOM/MOM, whilst the LOM fraction represents a more heteroatom and aliphatic rich component. Here we report Raman 2D maps and spectroscopic data for Murchison and Mighei, both before and after chemical degradation, which attacks and liberates LOM. The removal of LOM simulates the effects of aqueous alteration, where ester and ether bonds are broken and is thought to release some components to the soluble organic matter (SOM) fraction, also known as the free organic matter fraction (FOM). Raman spectroscopy can be used to reveal the nature of bonding (sp2 and sp3) within carbonaceous materials such as meteoritic organic matter, through evaluation of the D and G band peak centres and FWHM values from the recorded data. The presence of sp3 orbitals indicates that the organic materials contain aliphatic linkages and/or heteroatoms. Statistical analysis of the Raman parameters obtained here indicates that the organic matter originating the Raman response is indistinguishable between the bulk (chemically untreated) and chemically degraded (treated with KOH and HI) samples. Such an observation indicates that the ROM fraction is the major contributor to the Raman response of meteoritic organic matter and thus Raman spectroscopy is unlikely to record any aqueous alteration processes that have affected meteoritic organic matter. Therefore, studies which use Raman to probe the IOM are investigating just one of the compone

Journal article

Reddyhoff T, Ewen J, Deshpande P, Frogley M, Welch M, Montgomery Wet al., 2021, Macroscale superlubricity and polymorphism of long-chain n-alcohols, ACS Applied Materials and Interfaces, Vol: 13, Pages: 9239-9251, ISSN: 1944-8244

Simple n-alcohols, such as 1-dodecanol, show anomalous film-forming and friction behaviors under elastohydrodynamic lubrication (EHL) conditions, as found inside bearings and gears. Using tribometer, diamond anvil cell (DAC), and differential scanning calorimetry (DSC) experiments, we show that liquid 1-dodecanol undergoes a pressure-induced solidification when entrained into EHL contacts. Different solid polymorphs are formed inside the contact depending on the temperature and pressure conditions. Surprisingly, at a moderate temperature and pressure, 1-dodecanol forms a polymorph that exhibits robust macroscale superlubricity. The DAC and DSC experiments show that superlubricity is facilitated by the formation of lamellar, hydrogen-bonded structures of hexagonally close-packed molecules, which promote interlayer sliding. This novel superlubricity mechanism is similar to that proposed for the two-dimensional materials commonly employed as solid lubricants, but it also enables the practical advantages of liquid lubricants to be maintained. When the pressure is increased, 1-dodecanol undergoes a polymorphic transformation into a phase that gives a higher friction. The DAC and DSC experiments indicate that the high-friction polymorph is an orthorhombic crystal. The polymorphic transformation pressure coincides with the onset of a dimple formation in the EHL films, revealing that the anomalous film shapes are caused by the formation of rigid orthorhombic crystals inside the contact. This is the first demonstration of a macroscale superlubricity in an EHL contact lubricated by a nonaqueous liquid that arises from bulk effects rather than tribochemical transformations at the surfaces. Since the superlubricity observed here results from phase transformations, it is continuously self-replenishing and is insensitive to surface chemistry and topology. This discovery creates the possibility of implementing superlubricity in a wide range of machine components, which would resul

Journal article

Montgomery W, 2020, New Paths for Survivability of Organic Material in the Martian Subsurface, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 125, ISSN: 2169-9097

Journal article

Montgomery W, Jaramillo EA, Royle S, Kounaves S, Schulze-Makuch D, Sephton MAet al., 2019, Effects of oxygen-containing salts on the detection of organic biomarkers on Mars and in terrestrial analogue soils, Astrobiology, Vol: 19, Pages: 711-721, ISSN: 1531-1074

The detection of chlorinated hydrocarbons by Curiosity on Mars has been attributed to the presence of unidentified indigenous organic matter. Similarly, oxychlorines on Earth have been proposed to be responsible for the apparent lack of organics in the Atacama Desert. The presence of perchlorate (ClO4- ) poses a unique challenge to the measurement of organic matter due to the oxidizing power of oxychlorines during commonly used pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) methods. Here, we show that perchlorates and other oxyanion salts inhibit the detection of organic compounds, but that removing these problematic species prior to pyrolysis by using an optimal sample extraction duration and suitable ratios of water to sample mass enables analysis. We have characterized leached and unleached samples containing perchlorates from the Atacama Desert and have found that after leaching, the py-GC-MS chromatograms of the dried mineral residues show identifiable biomarkers associated with indigenous cyanobacteria. Samples which were pyrolyzed without leaching showed no detectable organic matter other than background siloxane and very weak or no trace of detectable polychlorinated benzenes Dried sample residues remaining after leaching, the mineral matrix and water-insoluble organic matter, showed a strong organic response in all cases when analyzed by py-GC-MS. These residues are most likely the product of the pyrolysis of water insoluble organics originally present in the samples. In addition, our results imply that previous soil analyses which contained high levels of oxyanions and concluded that organics were either not present, or at extremely low levels, should be re-examined.

Journal article

Verchovsky A, Hunt S, Montgomery W, Sephton MAet al., 2019, Reaction of Q to thermal metamorphism in parent bodies: Experimental simulation, Meteoritics and Planetary Science, Vol: 54, Pages: 558-572, ISSN: 1086-9379

Planetary noble gases in chondrites are concentrated in an unidentified carrier phase, called “Q.” Phase Q oxidized at relatively low temperature in pure oxygen is a very minor part of insoluble organic matter (IOM), but has not been separated in a pure form. High‐pressure (HP) experiments have been used to test the effects of thermal metamorphism on IOM from the Orgueil (CI1) meteorite, at conditions up to 10 GPa and 700 °C. The effect of the treatment on carbon structural order was characterized by Raman spectroscopy of the carbon D and G bands. The Raman results show that the IOM becomes progressively more graphite‐like with increasing intensity and duration of the HP treatment. The carbon structural transformations are accompanied by an increase in the release temperatures for IOM carbon and 36Ar during stepped combustion (the former to a greater extent than the latter for the most HP treated sample) when compared with the original untreated Orgueil (CI1) sample. The 36Ar/C ratio also appears to vary in response to HP treatment. Since 36Ar is a part of Q, its release temperature corresponds to that for Q oxidation. Thus, the structural transformations of Q and IOM upon HP treatment are not equal. These results correspond to observations of thermal metamorphism in the meteorite parent bodies, in particular those of type 4 enstatite chondrites, e.g., Indarch (EH4), where graphitized IOM oxidized at significantly higher temperatures than Q (Verchovsky et al. 2002). Our findings imply that Q is less graphitized than most of the macromolecular carbonaceous material present during parent body metamorphism and is thus a carbonaceous phase distinct from other meteoritic IOM.

Journal article

Royle SH, Oberlin E, Watson JS, Montgomery W, Kounaves SP, Sephton MAet al., 2018, Perchlorate‐driven combustion of organic matter during pyrolysis‐gas chromatography‐mass spectrometry: implications for organic matter detection on earth and mars, Journal of Geophysical Research: Planets, Vol: 123, Pages: 1901-1909, ISSN: 2169-9097

The search for life on Mars targets the detection of organic matter from extant or extinct organisms. Current protocols use thermal extraction procedures to transfer organic matter to mass spectrometer detectors. Oxidizing minerals on Mars, such as perchlorate, interfere with organic detection by thermal extraction. Thermal decomposition of perchlorate releases oxygen which promotes combustion of organic carbon. We have assessed the minimum mass ratio of organic carbon to perchlorate required to detect organic matter by thermal extraction and mass spectrometry. Locations on Mars with organic carbon to perchlorate ratios above 4.7-9.6 should be targeted. Because habitability is enhanced by the presence of liquid water and because perchlorate is a water soluble salt, locations on Mars with evidence of past or recent liquid water are high priority targets.

Journal article

Schulze-Makuch D, Wagner D, Kounaves SP, Mangelsdorf K, Devine KG, de Vera J-P, Schmitt-Kopplin P, Grossart H-P, Parro V, Kaupenjohann M, Galy A, Schneider B, Airo A, Frösler J, Davila A, Arens F, Caceres L, Cornejo FS, Carrizo D, Dartnell L, DiRuggiero J, Flury M, Ganzert L, Gessner MO, Grathwohl P, Guan L, Heinz J, Hess M, Keppler F, Maus D, McKay CP, Meckenstock RU, Montgomery W, Oberlin EA, Probst A, Saenz J, Sattler T, Schirmack J, Sephton MA, Schloter M, Uhl J, Valenzuela B, Vestergaard G, Wörmer L, Zamorano Pet al., 2018, A transitory microbial habitat in the hyperarid Atacama desert, Proceedings of the National Academy of Sciences, Vol: 115, Pages: 2670-2675, ISSN: 0027-8424

Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today’s extreme hyperaridity.

Journal article

Montgomery W, Sephton MA, Watson JS, Lewis JMT, Zeng Het al., 2018, The role of minerals in hydrogen sulfide generation during steam-assisted recovery of heavy oil, Energy and Fuels, Vol: 32, Pages: 4651-4654, ISSN: 0887-0624

Heavy oil is recovered from reservoirs using steam-assisted technology, which can lead to H2S generation if the oil is relatively sulfur-rich. We have used laboratory aquathermolysis to simulate the steam-assisted gravity drainage process and have compared free heavy oil to that contained within the mineral matrix. The presence of a mineral matrix was found to affect the amount of H2S produced and the chemical properties of the oil generated. Our findings show that H2S production is initiated by the presence of naturally occurring minerals at specific temperatures and pressures and production techniques that avoid these conditions will minimize H2S production.

Journal article

Royle SH, Montgomery W, Kounaves SP, Sephton MAet al., 2017, Effect of hydration state of Martian perchlorate salts on their decomposition temperatures during thermal extraction, Journal of Geophysical Research: Planets, Vol: 122, Pages: 2793-2802, ISSN: 2169-9097

Three Mars missions have analyzed the composition of surface samples using thermal extraction techniques. The temperatures of decomposition have been used as diagnostic information for the materials present. One compound of great current interest is perchlorate, a relatively recently discovered component of Mars' surface geochemistry that leads to deleterious effects on organic matter during thermal extraction. Knowledge of the thermal decomposition behavior of perchlorate salts is essential for mineral identification and possible avoidance of confounding interactions with organic matter. We have performed a series of experiments which reveal that the hydration state of magnesium perchlorate has a significant effect on decomposition temperature, with differing temperature releases of oxygen corresponding to different perchlorate hydration states (peak of O2 release shifts from 500 to 600°C as the proportion of the tetrahydrate form in the sample increases). Changes in crystallinity/crystal size may also have a secondary effect on the temperature of decomposition, and although these surface effects appear to be minor for our samples further investigation may be warranted. A less than full appreciation of the hydration state of perchlorate salts during thermal extraction analyses could lead to misidentification of the number and the nature of perchlorate phases present.

Journal article

Potiszil C, Montgomery W, Sephton MA, 2017, The Effects of Pressure on Model Compounds of Meteorite Organic Matter, ACS Earth and Space Chemistry, Vol: 1, Pages: 475-482, ISSN: 2472-3452

Extraterrestrial organic matter has been widely studied; however, its response to pressure has not. Primitive organic matter bearing meteorites, such as CI and CM carbonaceous chondrites, have experienced variable pressures, up to 10 GPa. To appreciate the effects of these pressures on the organic content of these bodies, the model compounds isophthalic acid, vanillin and vanillic acid were subjected to pressures of up to 11.5 GPa and subsequently decompressed. High resolution synchrotron source Fourier Transform Infrared (FTIR) was used to determine the effects of different benzene substituents at high pressure on both the vibrational assignments of the benzene core of the molecules and the ability of the aromatic compounds to form intermolecular hydrogen bonds. The presence of additional peaks at high pressure was found to coincide with molecules that contain carboxyl groups, these features are interpreted as C-H---O intermolecular hydrogen bonds. The formation of these hydrogen bonds has implications for the origination of macromolecular organic matter (MOM), owing to the importance of such attractive forces during episodes of cross linking, such as esterification. Pressure-induced hydrogen bond formation is a process by which aromatic MOM precursors could have cross linked to generate the organic polymers found within extraterrestrial bodies today.

Journal article

Montgomery WB, Watson JS, Potiszil C, Sephton MAet al., 2016, Sporopollenin, a natural copolymer, is robust under high hydrostatic pressure, Macromolecular Chemistry and Physics, Vol: 217, Pages: 2494-2500, ISSN: 1521-3935

Lycopodium sporopollenin, a natural copolymer, shows exceptional stability underhigh hydrostatic pressures (10 GPa) as determined by in situ high pressuresynchrotron source FTIR spectroscopy. This stability is evaluated in terms of thecomponent compounds of the sporopollenin: p-coumaric acid, phloretic acid, ferulicacid, and palmitic and sebacic acids, which represent the additional n-acid and ndiacidcomponents. This high stability is attributed to interactions between thesecomponents, rather than the exceptional stability of any one molecular component.We propose a biomimetic solution for the creation of polymer materials that canwithstand high pressures for a multitude of uses in aeronautics, vascular autografts,ballistics and light-weight protective materials.

Journal article

Montgomery W, Bromiley GD, Sephton MA, 2016, The nature of organic records in impact excavated rocks on Mars., Sci Rep, Vol: 6

Impact ejected rocks are targets for life detection missions to Mars. The Martian subsurface is more favourable to organic preservation than the surface owing to an attenuation of radiation and physical separation from oxidising materials with increasing depth. Impact events bring materials to the surface where they may be accessed without complicated drilling procedures. On Earth, different assemblages of organic matter types are derived from varying depositional environments. Here we assess whether these different types of organic materials can survive impact events without corruption. We subjected four terrestrial organic matter types to elevated pressures and temperatures in piston-cylinder experiments followed by chemical characterisation using whole-rock pyrolysis-gas chromatography-mass spectrometry. Our data reveal that long chain hydrocarbon-dominated organic matter (types I and II; mainly microbial or algal) are unresistant to pressure whereas aromatic hydrocarbon-dominated organic matter types (types III and IV; mainly land plant, metamorphosed or degraded, displaying some superficial chemical similarities to abiotic meteoritic organic matter) are relatively resistant. This suggests that the impact excavated record of potential biology on Mars will be unavoidably biased, with microbial organic matter underrepresented while metamorphosed, degraded or abiotic meteoritic organic matter types will be selectively preserved.

Journal article

Montgomery W, Sephton MA, 2016, Pressure effects in polycyclic aromatic nitrogenated heterocycles (PANHs): Diagnostic qualities and cosmobarometry potential, The Astrophysical Journal, Vol: 819, ISSN: 0004-637X

The influence of polycyclic aromatic nitrogen heterocycles (PANHs), which have been suggested as contributors to the interstellar IR emission bands, on interstellar emission features is difficult to constrain because their infrared characteristics are strongly similar to those for polycyclic aromatic hydrocarbons (PAHs). One possible solution is to seek a means of visualising the presence of PANHs that provides information which is distinct from that for PAHs. Although PANHs and PAHs have similar infrared characteristics in many settings, this relationship may not be universally maintained. We have used in-situ high pressure synchrotron-source Fourier transform infrared (FTIR) spectroscopy to determine that the responses of two representative molecules, acridine and anthracene, differ at high pressures (> ca. 1 GPa). Because there are a number of high pressure environments that can be remotely observed by infrared spectroscopy they represent a potential to glimpse the distribution of PANHs across the Cosmos.

Journal article

Montgomery W, Sephton MA, Watson JS, Zeng Het al., 2015, The effects of minerals on heavy-oil and bitumen chemistry when recovered by steam-assisted methods, Journal of Canadian Petroleum Technology, Vol: 54, Pages: 15-17, ISSN: 0021-9487

Research from this paper provides insight into the physical and chemical consequences of steam-assisted recovery of heavy oils and bitumens from sedimentary-rock reservoirs and reveals that geological and geochemical context is an essential consideration. To study mineral effects on gas production, the authors of the complete paper studied a well-characterized oil-containing core and the isolated crude oil from that core. The samples were run at 250 to 300° C in the continued presence of liquid water for 24 hours. The reaction products of all experiments include gases, oil flotate, oil sinkate, water-soluble products, and water-insoluble residues. All reaction products were studied with a variety of analytical techniques, including Fourier-transform infrared spectroscopy, chromatographic fractionation [saturate, resin, and asphaltene (SARA) analysis], gas chromatography mass spectrometry (GCMS), pyrolysis GCMS, and gas chromatography (GC) flame photometric detectors (FPDs)/thermal-conductivity detectors. These techniques were applied to whole oil, maltenes, and asphaltene fractions. Physical properties, including viscosity and density, were also measured.

Journal article

Montgomery WB, Sephton MA, Watson JS, Zeng H, Rees Aet al., 2015, Minimising hydrogen sulphide generation during steam assisted production of heavy oil, Scientific Reports, Vol: 5, ISSN: 2045-2322

The majority of global petroleum is in the form of highly viscous heavy oil. Traditionally heavy oil in sands at shallow depths is accessed by large scale mining activities. Recently steam has been used to allow heavy oil extraction with greatly reduced surface disturbance. However, in situ thermal recovery processes can generate hydrogen sulphide, high levels of which are toxic to humans and corrosive to equipment. Avoiding hydrogen sulphide production is the best possible mitigation strategy. Here we use laboratory aquathermolysis to reproduce conditions that may be experienced during thermal extraction. The results indicate that hydrogen sulphide generation occurs within a specific temperature and pressure window and corresponds to chemical and physical changes in the oil. Asphaltenes are identified as the major source of sulphur. Our findings reveal that for high sulphur heavy oils, the generation of hydrogen sulphide during steam assisted thermal recovery is minimal if temperature and pressure are maintained within specific criteria. This strict pressure and temperature dependence of hydrogen sulphide release can allow access to the world’s most voluminous oil deposits without generating excessive amounts of this unwanted gas product.

Journal article

Sephton MA, Lewis JMT, Watson JS, Montgomery W, Garnier Cet al., 2014, Perchlorate-induced combustion of organic matter with variable molecular weights: implications for Mars missions, Geophysical Research Letters, Vol: 41, Pages: 7453-7460, ISSN: 1944-8007

Instruments on the Viking landers and Curiosity rover analysed samples of Mars and detected carbon dioxide and organic compounds of uncertain origin. Mineral assisted reactions are leading to uncertainty, particularly those involving perchlorate minerals which thermally decompose to produce chlorine and oxygen which can then react with organic matter. Mineral assisted reactions produce organochlorine compounds and carbon dioxide. Although generally considered a problem for interpretation, the release profiles of generated gases can indicate the type of organic matter present. We have performed a set of experiments with perchlorate and organic matter of variable molecular weights. Results indicate that organic susceptibility to thermal degradation and mineral-assisted reactions is related to molecular weight. The natural occurrence and association of organic matter with differing molecular weights helps to discriminate between contamination (usually low molecular weight organic matter only) and indigenous carbon (commonly low and high molecular weight organic matter together). Our results can be used to provide insights into data returning from Mars.

Journal article

Verchovsky AB, Hunt SA, Montgomery W, Sephton MAet al., 2014, REACTION OF Q TO THERMAL METAMORPHISM IN THE PARENT BODIES: HIGH-PRESSURE EXPERIMENTS, 77th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A421-A421, ISSN: 1086-9379

Conference paper

Montgomery W, Watson JS, Sephton MA, 2014, An organic cosmo-barometer: Distinct pressure and temperature effects for methyl substituted polycyclic aromatic hydrocarbons, The Astrophysical Journal: an international review of astronomy and astronomical physics, Vol: 784, ISSN: 0004-637X

There are a number of key structures that can be used to reveal the formation and modification history of organic matter in the cosmos. For instance, the susceptibility of organic matter to heat is well documented and the relative thermal stabilities of different isomers can be used as cosmothermometers. Yet despite being an important variable, no previously recognized organic marker of pressure exists. The absence of a pressure marker is unfortunate considering our ability to effectively recognize extraterrestrial organic structures both remotely and in the laboratory. There are a wide variety of pressures in cosmic settings that could potentially be reflected by organic structures. Therefore, to develop an organic cosmic pressure marker, we have used state-of-the-art diamond anvil cell (DAC) and synchrotron-source Fourier transform infrared (FTIR) spectroscopy to reveal the effects of pressure on the substitution patterns for representatives of the commonly encountered methyl substituted naphthalenes, specifically the dimethylnaphthalenes. Interestingly, although temperature and pressure effects are concordant for many isomers, pressure appears to have the opposite effect to heat on the final molecular architecture of the 1,5-dimethylnaphthalene isomer. Our data suggest the possibility of the first pressure parameter or "cosmo-barometer" (1,5-dimethylnaphthalene/total dimethylnaphthalenes) that can distinguish pressure from thermal effects. Information can be obtained from the new pressure marker either remotely by instrumentation on landers or rovers or directly by laboratory measurement, and its use has relevance for all cases where organic matter, temperature, and pressure interplay in the cosmos.

Journal article

Montgomery W, Sephton MA, Watson J, Zeng Het al., 2014, The Effects Of Minerals On Heavy Oil And Bitumen Chemistry When Recovered Using Steam-assisted Methods, SPE Heavy Oil Conference-Canada

The production of gaseous sulfur-containing species during the steam-assisted recovery of heavy oil and bitumen have important consequences for both economics and safety. Factors such as the effects of mineral matrices require laboratory data to produce accurate models. To study mineral effects on gas production we studied a well-characterized oil-containing core and the isolated crude oil from that core. The samples were run at 250-300°C in the continued presence of liquid water for 24 hours. The reaction products of all experiments include gases, oil flotate, oil sinkate, water-soluble products, and water- insoluble residues. All reaction products were studied with a variety of analytical techniques, including FTIR spectroscopy, chromatographic fractionation (SARA analysis), GC-MS, pyrolysis GCMS and GC-FPD/TCD. These techniques were applied to whole oil, maltenes and asphaltene fractions. Physical properties including viscosity and density were also measured. Our data provide insights into the physical and chemical consequences of steam assisted recovery of heavy oils and bituments from sedimentary rock reservoirs and reveal that geological and geochemical context is an essential consideration.

Conference paper

Montgomery W, Lerch P, Sephton MA, 2014, In-situ vibrational optical rotatory dispersion of molecular organic crystals at high pressures, Analytica Chimica Acta, ISSN: 0003-2670

Organic structures respond to pressure with a variety of mechanisms including degradation, intramolecular transformation and intermolecular bonding. The effects of pressure on chiral organic structures are of particular interest because of the potential steric controls on the fate of pressurized molecules. Despite representing a range of opportunities, the simultaneous study of high pressures on different forms of chiral structures is poorly explored. We have combined synchrotron-source vibrational optical rotatory dispersion, micro-Fourier transform infrared spectroscopy and the use of a diamond anvil cell to simultaneously monitor the effects of pressure on the two enantiomers of the simple amino acid, alanine.

Journal article

Montgomery W, Watson JS, Sephton MA, 2014, An organic cosmo-barometer: Distinct pressure and temperature effects for methyl substituted polycyclic aromatic hydrocarbons, Astrophysical Journal, Vol: 784

There are a number of key structures that can be used to reveal the formation and modification history of organic matter in the cosmos. For instance, the susceptibility of organic matter to heat is well documented and the relative thermal stabilities of different isomers can be used as cosmothermometers. Yet despite being an important variable, no previously recognized organic marker of pressure exists. The absence of a pressure marker is unfortunate considering our ability to effectively recognize extraterrestrial organic structures both remotely and in the laboratory. There are a wide variety of pressures in cosmic settings that could potentially be reflected by organic structures. Therefore, to develop an organic cosmic pressure marker, we have used state-of-the-art diamond anvil cell (DAC) and synchrotron-source Fourier transform infrared (FTIR) spectroscopy to reveal the effects of pressure on the substitution patterns for representatives of the commonly encountered methyl substituted naphthalenes, specifically the dimethylnaphthalenes. Interestingly, although temperature and pressure effects are concordant for many isomers, pressure appears to have the opposite effect to heat on the final molecular architecture of the 1,5-dimethylnaphthalene isomer. Our data suggest the possibility of the first pressure parameter or "cosmo-barometer" (1,5-dimethylnaphthalene/total dimethylnaphthalenes) that can distinguish pressure from thermal effects. Information can be obtained from the new pressure marker either remotely by instrumentation on landers or rovers or directly by laboratory measurement, and its use has relevance for all cases where organic matter, temperature, and pressure interplay in the cosmos.

Journal article

Montgomery W, Court RW, Rees AC, Sephton MAet al., 2013, High temperature reactions of water with heavy oil and bitumen: insights into aquathermolysis chemistry during steam-assisted recovery, Fuel, Vol: 113, Pages: 426-426, ISSN: 0016-2361

To better understand the hot water-mediated organic transformation process (aquathermolysis) that occurs during the steam-assisted recovery of heavy oils and bitumen we have performed a series of experiments that subject a heavy oil to progressively higher temperatures and pressures in the presence of liquid water. As temperature and pressure increases, from ambient conditions to 300 °C and 1250 psig (8.6 MPa), a floating oil (flotate) is generated and is composed of mostly aliphatic hydrocarbons that appear to be generated at the expense of polars and asphaltenes. Analyses of hopane maturity parameters for the flotate indicate lower temperatures than the starting material suggesting the liberation of hopanes and, therefore, other hydrocarbons, from asphaltenes. Infrared spectra confirm changes in overall organic constitution as the relative abundance of hydrocarbons to oxygen-containing functional groups increases in the flotate. At the highest temperatures and pressures (325 °C, 1750 psig (13.8 MPa)) the flotate is at a maximum relative amount, the untransformed heavy oil is at a minimum and significant amounts of methane are generated indicating the onset of cracking. Steam-assisted recovery of heavy oil, therefore, leads to changes in the chemical constitution of a number of chemical fractions generating a lighter oil and gases that must be taken into account when planning field operations for production.

Journal article

Welch MD, Montgomery W, Balan E, Lerch Pet al., 2012, Insights into the high-pressure behavior of kaolinite from infrared spectroscopy and quantum-mechanical calculations, PHYSICS AND CHEMISTRY OF MINERALS, Vol: 39, Pages: 143-151, ISSN: 0342-1791

Journal article

Montgomery WB, Court RW, Watson JS, Sephton MA, Rees ACet al., 2012, Quantitative laboratory assessment of aquathermolysis chemistry during steam-assisted recovery of heavy oils and bitumen, World Heavy Oil Congress Paper WHOC12-402

In order to quantitatively study aquathermolysis chemistry during the thermal (steam-assisted) recovery of heavy oils & bitumen we have subjected a well-characterized heavy oil sample to 325°C and 2000 psi (13.8 MPa) in the continued presence of liquid water for 24 hours. The reaction products include gases, oil flotate, water-soluble products, and water-insoluble residues. All have been studied with a variety of analytical techniques, including FTIR spectroscopy, chromatographic fractionation (SARA analysis), and GC-MS. Results suggests that some in-situ upgrading of the oil occurs under these conditions. The methods discussed will be useful for the measurement of data to support model development for use in the engineering design of facilities for the thermal recovery of heavy oils and bitumen.

Conference paper

Verchovsky AB, Montgomery W, Sephton MA, 2011, Q NOBLE GASES IN THE ORGUEIL Hf/HCl RESIDUE: A HIGH PRESSURE EXPERIMENT, 74th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A244-A244, ISSN: 1086-9379

Conference paper

Montgomery W, Tuff J, Kohn SC, Jones RLet al., 2011, Reactions between organic acids and montmorillonite clay under Earth-forming conditions, CHEMICAL GEOLOGY, Vol: 283, Pages: 171-176, ISSN: 0009-2541

Journal article

Jennings E, Montgomery W, Lerch P, 2010, Stability of Coronene at High Temperature and Pressure, JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 114, Pages: 15753-15758, ISSN: 1520-6106

Journal article

Montgomery W, Crowhurst JC, Zaug JM, Jeanloz Ret al., 2008, The chemistry of cyanuric acid (H(3)C(3)N(3)O(3)) under high pressure and high temperature, JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 112, Pages: 2644-2648, ISSN: 1520-6106

Journal article

Zaug JM, Howard WM, Fried LE, Goncharov AF, Montgomery WB, Crowhurst JCet al., 2005, The Equation of State and Chemistry at Extreme Conditions. Applications to Detonation Products, Chemistry at Extreme Conditions, Pages: 399-429, ISBN: 9780444517661

The chapter explains the equation of the estate and chemistry at extreme conditions as applied to detonation products. Laboratory products conducted on materials held in excess of several kbar provide insight into a realm of chemical material properties that are significantly different from those encountered under ambient conditions. Dynamical simulation based on approximate Bonn-Oppenheimer potentials plays a large and increasingly important role in chemistry and in the biological and materials sciences. The chapter reviews the recent efforts to combine experimental and theoretical efforts to refine our knowledge of interatomic potentials and chemical processes at extreme conditions of pressure and temperature. The accuracy of the equation of state of polar fluids is significantly enhanced by using multi-species or cluster representation of the fluid. The methods to measure sound velocities of various super critical fluid systems are presented. The study of chemistry and kinetics of fluid under extreme conditions is explained with the help of the diamond anvil cell and the presence of CH2O2 during the detonation of some common explosion. Further resources are also provided. © 2005 Elsevier B.V. All rights reserved.

Book chapter

Montgomery W, Zaug JM, Howard WM, Goncharov AF, Crowhurst JC, Jeanloz Ret al., 2005, Melting curve and high-pressure chemistry of formic acid to 8 GPa and 600 K, JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 109, Pages: 19443-19447, ISSN: 1520-6106

Journal article

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