On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

ACS Catalysis ◽  
2021 ◽  
pp. 5718-5735
Author(s):  
Yutong Pang ◽  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anargyros Chatzidimitriou ◽  
Gaurav Kumar ◽  
...  
Keyword(s):  
Methyl Lactate ◽  
Spatial Design

scholarly journals On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

2021 ◽  
Author(s):  
Yutong Pang ◽  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anargyros Chatzidmitriou ◽  
Gaurav Kumar ◽  
...  
Keyword(s):  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Side Reaction ◽  
Acid Sites ◽  
Side Reactions ◽  
Proton Affinities ◽  
Nay Zeolite ◽  
Methyl Lactate ◽  
Diffusion Limitations ◽  
Spatial Design

Co-feeding an inert and site-selective chemical titrant provides desirable selectivity tuning when titrant adsorption is favored over side reaction pathways on a solid acid catalyst. Here, a selectivity enhancement from 61 to 84 C % was demonstrated for methyl lactate dehydration to methyl acrylate and acrylic acid over NaY zeolite catalyst using amines as the co-fed titrants to suppress side reactions on in situ generated Brønsted acid sites (BAS). The effectiveness of BAS titration was evaluated by considering both the basicity and steric properties of the titrant molecule with the goal to maximize the selectivity enhancement. The presence of electron-donating alkyl functional groups enhances amine basicity but also introduces additional steric constraints to the molecule with respect to the pore dimensions of the NaY zeolite. While higher basicity of titrant amines favors stronger adsorption on BAS, steric limitations hinder site binding through contributions from internal diffusion limitations and local steric repulsion between titrant and the zeolite wall around the BAS. Titrant bases with proton affinities above ~1040 kJ/mol and sizes below 85% of the NaY supercage window or pore diameter are predicted to afford dehydration selectivities above 90 C % to acrylate products.

scholarly journals On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

2021 ◽  
Author(s):  
Yutong Pang ◽  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anargyros Chatzidmitriou ◽  
Gaurav Kumar ◽  
...  
Keyword(s):  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Side Reaction ◽  
Acid Sites ◽  
Side Reactions ◽  
Proton Affinities ◽  
Nay Zeolite ◽  
Methyl Lactate ◽  
Diffusion Limitations ◽  
Spatial Design

Co-feeding an inert and site-selective chemical titrant provides desirable selectivity tuning when titrant adsorption is favored over side reaction pathways on a solid acid catalyst. Here, a selectivity enhancement from 61 to 84 C % was demonstrated for methyl lactate dehydration to methyl acrylate and acrylic acid over NaY zeolite catalyst using amines as the co-fed titrants to suppress side reactions on in situ generated Brønsted acid sites (BAS). The effectiveness of BAS titration was evaluated by considering both the basicity and steric properties of the titrant molecule with the goal to maximize the selectivity enhancement. The presence of electron-donating alkyl functional groups enhances amine basicity but also introduces additional steric constraints to the molecule with respect to the pore dimensions of the NaY zeolite. While higher basicity of titrant amines favors stronger adsorption on BAS, steric limitations hinder site binding through contributions from internal diffusion limitations and local steric repulsion between titrant and the zeolite wall around the BAS. Titrant bases with proton affinities above ~1040 kJ/mol and sizes below 85% of the NaY supercage window or pore diameter are predicted to afford dehydration selectivities above 90 C % to acrylate products.

Conversion of fructose into methyl lactate over SnO2/Al2O3 catalystin flow regime

2020 ◽  
pp. 43-47
Author(s):  
S.V. Prudius ◽  
◽  
N.L. Hes ◽  
A.M. Mylin ◽  
V.V. Brei ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Practical Interest ◽  
Dimethyl Acetal ◽  
Racemic Mixture ◽  
Process Conditions ◽  
Impregnation Method ◽  
Aqueous Methanol ◽  
Methyl Lactate ◽  
Al2o3 Catalyst ◽  
Target Reaction

In recent years, numerous researchers have focused on the development of catalytic methods for processing of biomass-derived sugars into alkyl lactates, which are widely used as non-toxic solvents and are the starting material for obtaining monomeric lactide. In this work, the transformation of fructose into methyl lactate on Sn-containing catalyst in the flow reactor that may be of practical interest was studied. The supported Sn-containing catalyst was ob-tained by a simple impregnation method of granular γ-Al2O3. The catalytic ex-periments were performed in a flow reactor at temperatures of 160-190 °C and pressure of 3.0 MPa. The 1.6-9.5 wt.% fructose solutions in 80% aqueous methanol were used as a reaction mixture. It was found that addition to a reac-tion mixture of 0.03 wt.% potassium carbonate leads to the increase in selec-tivity towards methyl lactate on 15% at 100% conversion of fructose. Prod-ucts of the target reaction С6Н12О6 + 2СН3ОН = 2С4Н8О3 + 2Н2О were ana-lyzed using 13C NMR method. The following process conditions for obtaining of 65 mol% methyl lactate yield at 100% fructose conversion were found: use of 4.8 wt.% fructose solution in 80% methanol, 180 °С, 3.0 МПа and a load on catalyst 1.5 mmol C6H12O6/mlcat/h at contact time of 11 minutes. The cata-lyst productivity is 2.0 mmol C4H8O3/mlcat/h and the by-productі are 1,3-dihydroxyacetone dimethyl acetal (20%) and 5-hydroxymethylfurfural (10%). It should be noted that a racemic mixture of L- and D-methyl lactates has been obtained by conversion of D-fructose on the SnO2/Al2O3 catalyst. The SnO2/Al2O3 catalyst was found to be stable for 6 h while maintaining full fruc-tose conversion at 55–70% methyl lactate selectivity. After regeneration the catalyst completely restores the initial activity.

Journal of Korea Intitute of Spatial Design

10.35216/kisd ◽  
2020 ◽  
Keyword(s):  
Spatial Design

Conversion of Biomass-Derived Carbohydrates to Methyl Lactate Using Sn-MCM-41 and SnO2/SiO2

2013 ◽  
Vol 33 (10) ◽  
pp. 1696-1705
Author(s):  
Zhen LIU ◽  
Gang FENG ◽  
Chunyan PAN ◽  
Wang LI ◽  
Ping CHEN ◽  
...  
Keyword(s):  
Methyl Lactate ◽  
Mcm 41

scholarly journals Mechanical Properties of Graphene Oxide Coupled by Multi-Physical Field: Grain Boundaries and Functional Groups

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Grain Boundaries ◽  
Functional Groups ◽  
Oxygen Content ◽  
Tensile Fracture ◽  
Hydroxyl Groups ◽  
Molecular Configuration ◽  
Spatial Design ◽  
Out Of Plane

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.

Norfolk’s “Model Prison Community”: Howard Belding Gill and the Social Process of Prison Reform

2021 ◽  
Vol 101 (2) ◽  
pp. 127-146
Author(s):  
Matthew DelSesto
Keyword(s):  
Criminal Justice ◽  
Social Process ◽  
Prison Reform ◽  
Criminal Justice Reform ◽  
Spatial Design ◽  
The Social ◽  
Public Consciousness ◽  
Prison Community ◽  
The Relationship

This article explores the social process of criminal justice reform, from Howard Belding Gill’s 1927 appointment as the first superintendent of the Norfolk Prison Colony to his dramatic State House hearing and dismissal in 1934. In order to understand the social and spatial design of Norfolk’s “model prison community,” this article reviews Gills’ tenure as superintendent through administrative documents, newspaper reports, and his writings on criminal justice reform. Particular attention is given to the relationship between correctional administration and public consciousness. Concluding insights are offered on the possible lessons from Norfolk Prison Colony for contemporary reform efforts.

scholarly journals Role of Spatial Design in Green Buildings-A Critical Review of Green Building Rating Systems

2021 ◽  
Vol 1116 (1) ◽  
pp. 012166
Author(s):  
Manoj Katiyar ◽  
Ashok Kumar Sahu ◽  
Sanjay Agarwal ◽  
Pravesh Tiwari
Keyword(s):  
Critical Review ◽  
Green Building ◽  
Green Buildings ◽  
Rating Systems ◽  
Spatial Design
Sign in / Sign up

Export Citation Format

Share Document