Master of Science

thesisThis thesis focused on exploring the economic limitations for the development of western oil shale. The analysis was developed by scaling a known process and simulating in ProMax some of the chemical processes implicated in the production of oil shale, obtaining the capital and operating costs to develop these processes and performing an economic evaluation. The final results are a detailed breakdown of the components of the supply cost of syn crude produced. Two technologies were considered in this project: air-fired combustors and oxyfired combustors with a CO2 capture course of action. Additionally, in each of the scenarios, a sensitivity analysis was performed based on the resource quality and the taxation of CO2 emissions for the air-fired combustion and the price of CO2 for oxy-fired combustion. This project revealed that the total capital invested to develop oil shale projects is gargantuan: a total depreciable capital cost of $3.34 and$3.39 billion for the air and oxyfired case, respectively, for a shale quality of 25 gal/ton. It was shown that the geological resource significantly impacts the cost of production. For different shale grades of 20, 25 and 35 gal/ton, the supply cost varied from $124/bbl,$112/bbl and $97/bbl, respectively. Moreover, this analysis showed that the oil shale project profitability is highly dependent on governmental policies. The potential taxation of CO2 increased the supply cost by 1.75$112/bbl and with CO2 taxation increased to $120/bbl. From these results, it can be concluded that oil shale projects have higher technical, economic and government policy risks which limit their use by industry. For more projects to move forward, these risks must be lowered. It also is clear from the supply cost analysis that royalties are a major component as are taxes and interest charges

Mechanochemical co-crystallization:Insights and predictions

Mechanochemistry integrates mechanical and chemical phenomena to spawn new modes of reactivity, faster reaction kinetics and the discovery of novel materials, in a solvent-free and environmental manner. This simple, yet efficient technique has become a well-established screening technique to discover pharmaceutical co-crystals - components that incorporate a secondary crystalline structure into the lattice of an active pharmaceutical ingredient (API) to improve its physicochemical properties. Today, predicting the reactivity of solid-state materials under mechanochemical conditions remains a major challenge. Here, we explore various machine learning algorithms and identified XGBoost ideal to accurately predict mechanochemical co-crystallization. The model was trained using 1000 co-crystallization events and 2083 chemical descriptors, revealing fundamental insights about mechanochemistry. The model was implemented to screen secondary crystalline structures against a model API, yielding three new mechanochemically-formed co-crystals. This predictive model will accelerate the discovery of novel pharmaceuticals while its insights aid at developing a more sustainable chemical industry.</p

Mechanochemical co-crystallization:Insights and predictions

Mechanochemistry integrates mechanical and chemical phenomena to spawn new modes of reactivity, faster reaction kinetics and the discovery of novel materials, in a solvent-free and environmental manner. This simple, yet efficient technique has become a well-established screening technique to discover pharmaceutical co-crystals - components that incorporate a secondary crystalline structure into the lattice of an active pharmaceutical ingredient (API) to improve its physicochemical properties. Today, predicting the reactivity of solid-state materials under mechanochemical conditions remains a major challenge. Here, we explore various machine learning algorithms and identified XGBoost ideal to accurately predict mechanochemical co-crystallization. The model was trained using 1000 co-crystallization events and 2083 chemical descriptors, revealing fundamental insights about mechanochemistry. The model was implemented to screen secondary crystalline structures against a model API, yielding three new mechanochemically-formed co-crystals. This predictive model will accelerate the discovery of novel pharmaceuticals while its insights aid at developing a more sustainable chemical industry.</p

The Effect of Jet Flow Impingement on the Corrosion Products formed on a Pipeline Steel in Naturally Aerated Sour Brine

Corrosion was generated by the action of a jet impingement flow of sour brine on pipeline steel samples of X70. Flow-assisted corrosion affected nature, number and peak intensity of the chemical species formed as corrosion products. Iron sulfides predominated in static and low flow rate conditions (1.1 m/s), whereas at 2.4 m/s iron oxides were mainly formed, which led to higher corrosion rates and suggested that oxides are less protective than sulfides. On inhibition, imidazoline seems to mitigate oxide formation and support sulfide formation balancing both species on steel surface. Ferrite phase in laminar pearlite was preferentially dissolved with/without inhibitor, and mackinawite (FeS2) was formed at every flow rate, angle with and without inhibitor. Theoretical stresses determined by computational flow dynamics for corrosion product removal showed a fair approximation to those proposed in the literature

Elusive Seed Formation via Electrical Confinement: Control of a Novel Cocrystal in Cooling Crystallization

Pharmaceutical cocrystals are multicomponent materials formed to enhance the properties of active pharmaceutical ingredients (APIs) and are commercially used to increase the number of drug candidates that successfully make it through the drug discovery pipeline. Nevertheless, the industrial production of cocrystals and other elusive solid forms remains a challenge. The main limitations are due to challenges related to the scale-up, solid-form control, and undesirable parameters needed for the preparation method. This study leverages the features of electrospray crystallization to generate elusive cocrystal forms that contain the API acetaminophen (paracetamol) and its regioisomer metacetamol. We report the formation of a new cocrystal, which is held together by van der Waals interactions, and the use of the newly electrosprayed cocrystals as seeds to tune the performance of cooling crystallization, allowing this commonly used crystallization method to produce the elusive cocrystal. The electrosprayed cocrystal displays a previously unseen sponge-like surface topology and a fourfold solubility enhancement over those found for single-component APIs. This new technology expands the accessibility to new solid forms that were previously inaccessible by other crystallization methods.</p

A comparative study of oxygen diffusion in PET and PEF using molecular modelling:Computational Insights into the Mechanism for Gas Transport in Bulk Polymer Systems

Bio-derived polyethylene furanoate (PEF) has recently gained attention as a sustainable alternative to polyethylene terephthalate (PET), amidst environmental concerns over fossil fuel depletion. Herein, we outline a computational approach to investigate the tenfold difference in barrier properties between the two materials, using a statistically robust methodology to predict diffusion coefficients from molecular dynamics simulation. Oxygen diffusion was predicted to a high level of accuracy, at 3.24 × 10–8 and 2.88 × 10–9 cm2 s–1 for PET and PEF, respectively (Dexperimental = 1.16 × 10–8 and 1.04 × 10–9 cm2 s–1). Simulations quantifiably demonstrated the contributions of ring-flipping chain dynamics on oxygen diffusion, and novel Monte Carlo techniques revealed atomistic insights into the mechanism by which this occurs. Areas of accessible volume within the polymer matrix were seen to converge to facilitate lateral oxygen displacement. Infrequent convergences in PEF, due to subdued polymer chain dynamics and higher system density, accounted for the slower oxygen diffusion relative to PET

Xylose-Based Polyethers and Polyesters Via ADMET Polymerization toward Polyethylene-Like Materials:ACS Applied Polymer Materials

One of the challenges of developing bioderived polymers is to obtain materials with competitive properties. This study investigates the structure-properties relationships of polyesters and polyethers that can be derived from d-xylose through metathesis polymerization, in order to produce bioderived plastic materials that are sourced from sustainable feedstocks and whose properties can compete with those of polyolefins such as polyethylene. Bicyclic diol 1,2-O-isopropylidene-α-d-xylofuranose was coupled with ω-unsaturated fatty acids and alcohols of different chain lengths (C11, C5, C3), and the resulting α,ω-unsaturated esters and ethers polymerized via an acyclic diene metathesis (ADMET) polymerization using a commercial Grubbs second-generation catalyst, obtaining polymers with Mn up to 63.0 kg mol–1. Glass transition temperatures (Tg) decreased linearly with increasing chain length and were lower for polyethers (−32 to 14 °C) compared to polyesters (−14 to 45 °C). ADMET polymers could be modified postpolymerization by reacting their internal carbon–carbon double bonds. Thiol–ene reaction with methyl thioglycolate lowered the Tg while allowing insertion of additional functional groups. Alkene hydrogenation turned the polyester and polyether with C20 hydrocarbon linkers into semicrystalline polymers with Tm ≈ 50 °C. The latter, when cast into films, displayed remarkable polyethylene-like properties. Hot-pressed films proved ductile materials (Young modulus Ey 60–110 MPa, elongation at break εb 670–1000%, ultimate tensile strength σb 8–10 MPa), while uniaxially oriented films proved very strong yet flexible materials (Ey 190–200 MPa, εb 160–350%, σb 43–66 MPa). Gas barrier properties were comparable to those of commercial polyolefins. Polyethers were resistant to hydrolysis, while polyesters depolymerized under alkaline conditions

An evaluation of the Johanson model for roller compaction process development for a high dose API

Roller compaction (RC) is a dry granulation technique applied to improve the flow and compressibility of drug formulations. RC implementation for high drug load formulations can be challenging due to flow issues and a high consumption of active pharmaceutical ingredient (API) for robust process development. This work addresses these challenges using process modelling for design and scale-up of an RC process on the same equipment and transfer to different equipment. A modified application of existing models incorporating a new description of mass transport in the feed screw is evaluated for guaifenesin formulations with a 90% drug loading. The model is calibrated using low-throughput data on a Vector Freund TF Mini RC and used to predict ribbon density and throughput for various process settings at high-throughput. It is found that the modelling framework can reasonably predict high-throughput behaviour on the same RC but the predictive performance decreases for transfer between equipment.</p

Heat-reflux processing of black peppercorn into bioactive antioxidant oleoresins:a three-functioned Taguchi-based grey relational grading

The focus of this research is to identify the best set of factors that influence the heat-reflux recovery of total phenolic content and antioxidant activities under multiple quality characteristics. Parametric Taguchi L9 orthogonal design and grey relational analysis technique were used to investigate the effect of three variables—reflux duration, particle size, and feed-to-solvent ratio on the multiple responses of total phenolic contents, DPPH, and H2O2 activities. According to the grey relational grades response table, the ideal number of criteria for the heat reflux results were 120 min of reflux duration, 0.2 mm of particle size, and a feed-solvent ratio of 1:16. The total phenolic content, DPPH, and H2O2 scavenging activities were measured as 35.23 ± 0.004 mgGAE/g d.w, 107.57 ± 0.04 g/mL, and 87.78 ± 0.32 g/mL, respectively. Moreover, with the Levenberg–Marquardt (LM) neural network architecture, the trained network has a mean square error (MSE) of 3.7646E−07 and an R2 of 0.9500 as the training function outcome, indicating a significant predicted endpoint. The confirmatory experimental results show a 41.9 per cent improvement in relation to the predicted values. The results of this study indicated that, optimising the heat reflux process would be an innovative and beneficial approach for preparing bioactive compounds from functional plants, resulting in cost savings while increasing antioxidant capacity and overall phenolic recovery

Heat-reflux processing of black peppercorn into bioactive antioxidant oleoresins:a three-functioned Taguchi-based grey relational grading

The focus of this research is to identify the best set of factors that influence the heat-reflux recovery of total phenolic content and antioxidant activities under multiple quality characteristics. Parametric Taguchi L9 orthogonal design and grey relational analysis technique were used to investigate the effect of three variables—reflux duration, particle size, and feed-to-solvent ratio on the multiple responses of total phenolic contents, DPPH, and H2O2 activities. According to the grey relational grades response table, the ideal number of criteria for the heat reflux results were 120 min of reflux duration, 0.2 mm of particle size, and a feed-solvent ratio of 1:16. The total phenolic content, DPPH, and H2O2 scavenging activities were measured as 35.23 ± 0.004 mgGAE/g d.w, 107.57 ± 0.04 g/mL, and 87.78 ± 0.32 g/mL, respectively. Moreover, with the Levenberg–Marquardt (LM) neural network architecture, the trained network has a mean square error (MSE) of 3.7646E−07 and an R2 of 0.9500 as the training function outcome, indicating a significant predicted endpoint. The confirmatory experimental results show a 41.9 per cent improvement in relation to the predicted values. The results of this study indicated that, optimising the heat reflux process would be an innovative and beneficial approach for preparing bioactive compounds from functional plants, resulting in cost savings while increasing antioxidant capacity and overall phenolic recovery