scholarly journals Machine learning and molecular descriptors enable rational solvent selection in asymmetric catalysis

2019 ◽  
Vol 10 (27) ◽  
pp. 6697-6706 ◽  
Author(s):  
Yehia Amar ◽  
Artur M. Schweidtmann ◽  
Paul Deutsch ◽  
Liwei Cao ◽  
Alexei Lapkin

Rational solvent selection remains a significant challenge in process development.

2021 ◽  
Author(s):  
Amir Al Ghatta ◽  
James D. E. T. Wilton-Ely ◽  
Jason P. Hallett

Process simulations allow the evaluation of the emissions and selling price for the production of the key monomer FDCA based on different feedstocks and solvent systems, alongside considerations of safety and current process development.


2021 ◽  
Author(s):  
Simone Gallarati ◽  
Raimon Fabregat ◽  
Ruben Laplaza ◽  
Sinjini Bhattacharjee ◽  
Matthew D. Wodrich ◽  
...  

HHundreds of catalytic methods are developed each year to meet the demand for high-purity chiral compounds. The computational design of enantioselective organocatalysts remains a significant challenge, as catalysts are typically...


Synlett ◽  
2020 ◽  
Author(s):  
Shuo-Qing Zhang ◽  
Xin Hong ◽  
Li-Cheng Xu ◽  
Xin Li ◽  
Miao-Jiong Tang ◽  
...  

AbstractDescription of molecular stereostructure is critical for the machine learning prediction of asymmetric catalysis. Herein we report a spherical projection descriptor of molecular stereostructure (SPMS), which allows precise representation of the molecular van der Waals (vdW) surface. The key features of SPMS descriptor are presented using the examples of chiral phosphoric acid, and the machine learning application is demonstrated in Denmark’s dataset of asymmetric thiol addition to N-acylimines. In addition, SPMS descriptor also offers a color-coded diagram that provides straightforward chemical interpretation of the steric environment.


2021 ◽  
Vol 9 (1) ◽  
pp. 55-62
Author(s):  
Geoferleen Flores ◽  
◽  
Eduardo Jr. Piedad ◽  
Anzeneth Figueroa ◽  
Romari Tumamak ◽  
...  

Traffic flow mismanagement is a significant challenge in all countries especially in crowded cities. An alternative solution is to utilize smart technologies to predict traffic flow. In this study, frequency spectrum describing traffic sound characteristics is used as an indicator to predict the next five-minute vehicle density. Sound frequency and vehicle intensity are collected during a thirteen-hour data gathering. The collected sound intensity and frequency are then used to learn three machine-learning models - support vector machine, artificial neural network, and random forest and to predict vehicle intensity. It was found out that the performances of the three models based on root-mean-square-error values are 12.97, 16.01, and 10.67, respectively. These initial and satisfactory results pave a new way to predict traffic flow based on traffic sound characteristics which may serve as a better alternative to conventional features.


2020 ◽  
Author(s):  
Xinzhe Zhu ◽  
Chi-Hung Ho ◽  
Xiaonan Wang

<p><a></a><a>The production process of many active pharmaceutical ingredients such as sitagliptin could cause severe environmental problems due to the use of toxic chemical materials and production infrastructure, energy consumption and wastes treatment. The environmental impacts of sitagliptin production process were estimated with life cycle assessment (LCA) method, which suggested that the use of chemical materials provided the major environmental impacts. Both methods of Eco-indicator 99 and ReCiPe endpoints confirmed that chemical feedstock accounted 83% and 70% of life-cycle impact, respectively. Among all the chemical materials used in the sitagliptin production process, </a><a>trifluoroacetic anhydride </a>was identified as the largest influential factor in most impact categories according to the results of ReCiPe midpoints method. Therefore, high-throughput screening was performed to seek for green chemical substitutes to replace the target chemical (i.e. trifluoroacetic anhydride) by the following three steps. Firstly, thirty most similar chemicals were obtained from two million candidate alternatives in PubChem database based on their molecular descriptors. Thereafter, deep learning neural network models were developed to predict life-cycle impact according to the chemicals in Ecoinvent v3.5 database with known LCA values and corresponding molecular descriptors. Finally, 1,2-ethanediyl ester was proved to be one of the potential greener substitutes after the LCA data of these similar chemicals were predicted using the well-trained machine learning models. The case study demonstrated the applicability of the novel framework to screen green chemical substitutes and optimize the pharmaceutical manufacturing process.</p>


2022 ◽  
Author(s):  
Andrea Angulo ◽  
Lankun Yang ◽  
Eray S Aydil ◽  
Miguel A. Modestino

Autonomous chemical process development and optimization methods use algorithms to explore the operating parameter space based on feedback from experimentally determined exit stream compositions. Measuring the compositions of multicomponent streams...


2021 ◽  
Vol 11 (24) ◽  
pp. 11684
Author(s):  
Mona Khalifa A. Aljero ◽  
Nazife Dimililer

Detecting harmful content or hate speech on social media is a significant challenge due to the high throughput and large volume of content production on these platforms. Identifying hate speech in a timely manner is crucial in preventing its dissemination. We propose a novel stacked ensemble approach for detecting hate speech in English tweets. The proposed architecture employs an ensemble of three classifiers, namely support vector machine (SVM), logistic regression (LR), and XGBoost classifier (XGB), trained using word2vec and universal encoding features. The meta classifier, LR, combines the outputs of the three base classifiers and the features employed by the base classifiers to produce the final output. It is shown that the proposed architecture improves the performance of the widely used single classifiers as well as the standard stacking and classifier ensemble using majority voting. We also present results on the use of various combinations of machine learning classifiers as base classifiers. The experimental results from the proposed architecture indicated an improvement in the performance on all four datasets compared with the standard stacking, base classifiers, and majority voting. Furthermore, on three of these datasets, the proposed architecture outperformed all state-of-the-art systems.


Science ◽  
2020 ◽  
Vol 367 (6478) ◽  
pp. 638.5-639
Author(s):  
Jake Yeston

2016 ◽  
Vol 18 (24) ◽  
pp. 6564-6572 ◽  
Author(s):  
Valerio Isoni ◽  
Loretta L. Wong ◽  
Hsien H. Khoo ◽  
Iskandar Halim ◽  
Paul Sharratt

A practicable, LCA based methodology has been developed to evaluate the sustainability implications of solvent selection during early process development for a batch manufacturing process for an API.


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