Dehydration Reactions in Water. Surfactant-Type Brønsted Acid-Catalyzed Direct Esterification of Carboxylic Acids with Alcohols in an Emulsion System

Manabe, Kei; Sun, Xiang‐Min; Kobayashi, Shū

doi:10.1021/ja016338q

Cited by 208 publications

(74 citation statements)

References 31 publications

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“…ii) Exposed hydrophobic clusters and patches are common on today's proteins. A study of 112 soluble monomeric proteins (78) (84,85), such as protein surfaces. Second, a major route of protein synthesis in simple organisms, such as bacteria and fungi, uses nonribosomal peptide synthetases, which do not involve mRNAs (86,87).…”

Section: "Flory Length Problem": Polymerization Processes Produce Mosmentioning

confidence: 99%

Foldamer hypothesis for the growth and sequence differentiation of prebiotic polymers

Guseva

Zuckermann

Dill

2017

Proc. Natl. Acad. Sci. U.S.A.

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It is not known how life originated. It is thought that prebiotic processes were able to synthesize short random polymers. However, then, how do short-chain molecules spontaneously grow longer? Also, how would random chains grow more informational and become autocatalytic (i.e., increasing their own concentrations)? We study the folding and binding of random sequences of hydrophobic (H) and polar (P) monomers in a computational model. We find that even short hydrophobic polar (HP) chains can collapse into relatively compact structures, exposing hydrophobic surfaces. In this way, they act as primitive versions of today's protein catalysts, elongating other such HP polymers as ribosomes would now do. Such foldamer catalysts are shown to form an autocatalytic set, through which short chains grow into longer chains that have particular sequences. An attractive feature of this model is that it does not overconverge to a single solution; it gives ensembles that could further evolve under selection. This mechanism describes how specific sequences and conformations could contribute to the chemistry-to-biology (CTB) transition.origin of life | HP model | biopolymers | autocatalytic sets A mong the most mysterious processes in chemistry is how the spontaneous transition occurred more than 3 billion years ago from a soup of prebiotic molecules to living cells. What was the mechanism of the chemistry-to-biology (CTB) transition? In this paper, we develop a model to explore how prebiotic polymerization processes might have produced long chains of proteinlike or nucleic acid-like molecules (1, 2). What polymerization processes are autocatalytic? How could they have produced long chains? Also, how might random chain sequences have become informational and self-serving? Our questions here are about physical spontaneous mechanisms, not about specific monomer or polymer chemistries. CTB Requires an Autocatalytic ProcessEarly on, it was recognized that the transition from simple chemistry to self-supporting biological behavior requires autocatalysis (i.e., some form of positive feedback or bootstrapping, in which the concentrations of some molecules become amplified and selfsustaining relative to other molecules) (3-8). That work has led to the idea of an autocatalytic set, a collection of entities in which any one entity can catalyze another.We first review some of the key results. A class of models called Graded Autocatalysis Replication Domain (GARD) (9-11) predicts that artificial autocatalytic chemical kinetic networks can lead to self-replication, with a corresponding amplification of some chemicals over others. Such systems display some degree of inheritance and adaptability. GARD model is a subset of metabolism first models, which envision that small molecule chemical processes precede information transfer and precede the first biopolymers. Focusing on polymers, Wu and Higgs (12) developed a model of RNA chain-length autocatalysis. They envision that some of the RNA chains can spontaneously serve as polymerase ribozymes, l...

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Section: "Flory Length Problem": Polymerization Processes Produce Mosmentioning

confidence: 99%

Foldamer hypothesis for the growth and sequence differentiation of prebiotic polymers

Guseva

Zuckermann

Dill

2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Manabe et al investigated the esterification and other dehydrative reactions catalyzed by p-dodecylbenzenesulfonic acid, an acidic surfactant, in emulsions of carboxylic acids and alcohol. Their results showed that the reactants and the products have to be sufficiently hydrophobic to exclude water from the reaction site, and ideally, the catalyst can also act as a surfactant [44,45].…”

Section: Small Moleculesmentioning

confidence: 99%

Enzymatic Catalysis at Interfaces—Heterophase Systems as Substrates for Enzymatic Action

Weiss

Landfester

2013

Catalysts

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Several important enzymatic reactions occurring in nature, such as, e.g., the digestion of fat, proceed only at the interface of two immiscible phases. Typically, these systems consist of an organic substrate, dispersed in an aqueous continuous phase, with a specialized enzyme capable of working at the interface. For adopting such a system for organic synthesis, a stable heterophase system with a large interfacial area is required. These prerequisites can be found in so-called miniemulsions. Such liquid-liquid heterophase systems feature droplets with sizes smaller than 500 nm, and more importantly, these emulsions do not suffer from Ostwald ripening, as conventional emulsions do. Consequently, the droplets show long-term stability, even throughout reactions conducted in the droplets. In this review, we will briefly discuss the physicochemical background of miniemulsions, provide a comprehensive overview of the enzymatically catalyzed reactions conducted in miniemulsions and, as data are available, to compare the most important features to conventional systems, as reverse microemulsions, (macro)emulsions and solvent-based systems.

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“…To address the drawbacks of both liquid and solid acids, a novel catalytic system, for example, colloidal dispersion or reverse micelles, formed by Brønsted acidsurfactant-combined catalyst, has been reported (6). For example, Kabayashi et al reported dodecylbenzene sulfonic acid (DBSA)-catalyzed esterification of carboxylic acids and alcohols in water (7,8). In these reactions, DBSA and substrates were able to form emulsion droplets, whose interior was hydrophobic enough to exclude water molecules generated during the reactions.…”

Section: Introductionmentioning

confidence: 99%

Esterification synthesis of ethyl oleate catalyzed by Brønsted acid–surfactant-combined ionic liquid

Zheng

Yang

et al. 2017

Green Chemistry Letters and Reviews

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ABSTRACT3-(N,N-dimethyldodecylammonium) propanesulfonic acid hydrogen sulfate [HSO 4 ]), a Brønsted acidic-surfactant-combined ionic liquid, was successfully prepared from cheap materials and applied to catalyze the esterification synthesis of ethyl oleate using oleic acid and ethanol as precursors. The produced condition of oleic acid ethyl ester was optimized including the amount of catalyst, reaction time, molar ratio and content of water. Under optimal condition (ethanol to oleic acid molar ratio, 3:1; amount of the catalyst, 5 wt% (based on the mass of oleic acid); reaction time, 3 h; reaction temperature, 78°C; and content of water, 0.4 wt%), the conversion of oleic acid was over 97%. Due to the reverse micelles formed by [HSO 4 ], the microreactor not only promoted the esterification toward the desired side of the ester, but also avoided the hydrolysis of ester. Moreover, the [SB3-12][HSO 4 ] could be reused by a simple decantation separating process and noticeable loss of catalytic activity was not observed even after being recycled for five cycles. The green system offers several advantages, such as excellent yield, efficient catalytic activity, free-solvent and simple operational procedure. ARTICLE HISTORY

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Dehydration Reactions in Water. Surfactant-Type Brønsted Acid-Catalyzed Direct Esterification of Carboxylic Acids with Alcohols in an Emulsion System

Cited by 208 publications

References 31 publications

Foldamer hypothesis for the growth and sequence differentiation of prebiotic polymers

Foldamer hypothesis for the growth and sequence differentiation of prebiotic polymers

Enzymatic Catalysis at Interfaces—Heterophase Systems as Substrates for Enzymatic Action

Esterification synthesis of ethyl oleate catalyzed by Brønsted acid–surfactant-combined ionic liquid

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