Hydroxyalkylation of Cyclic Imides with Oxiranes. Part II. The Mechanism of Reaction in Presence of Triethylamine

Lubczak, Jacek

doi:10.4236/ojpc.2012.22013

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…Thus, the fast consumption of GL is not due to the reaction with the CS WS but to the presence of the amine groups in the structure of the CS WS merely, which catalyzed the reaction between water and GL (compare with Scheme 6 ). Such catalysis by the amines in the hydroxyalkylation reactions with epoxide is known [ 46 ].…”

Section: Resultsmentioning

confidence: 99%

Chitosan Oligomer as a Raw Material for Obtaining Polyurethane Foams

Strzałka

Lubczak

2023

Polymers

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Decreasing oil extraction stimulates attempts to use biologically available sources to produce polyols, which are the basic components for obtaining polyurethane foams. Plants are inexhaustible source of oils, sugars, starches, and cellulose. Similar substrates to obtain polyols are chitosans. Commercially available modified chitosans are soluble in water, which gives them the possibility to react with hydroxyalkylating agents. We used a water-soluble chitosan previously to obtain polyols suitable for producing rigid polyurethane foams. Here, we described hydroxyalkylation of a low-molecular-weight chitosan (oligomeric chitosan) with glycidol and ethylene carbonate to obtain polyols. The polyols were isolated and studied in detail by IR, 1H-NMR, and MALDI–ToF methods. Their properties, such as density, viscosity, surface tension, and hydroxyl numbers, were determined. The progress of the hydroxyalkylation reaction of water-soluble chitosan and chitosan oligomer with glycidol was compared in order to characterize the reactivity and mechanism of the process. We found that the hydroxyalkylation of chitosan with glycidol in glycerol resulted in the formation of a multifunctional product suitable for further conversion to polyurethane foams with favorable properties. The straightforward hydroxyalkylation of chitosan with glycidol was accompanied by the oligomerization of glycidol. The hydroxyalkylation of chitosan with glycidol in the presence of ethylene carbonate was accompanied by minor hydroxyalkylation of chitosan with ethylene carbonate. The chosen polyols were used to obtain rigid polyurethane foams which were characterized by physical parameters such as apparent density, water uptake, dimension stability, heat conductance, compressive strength, and heat resistance at 150 and 175 °C. The properties of polyurethane foams obtained from chitosan-oligomer and water-soluble-chitosan sources were compared. Polyurethane foams obtained from polyols synthesized in the presence of glycerol had advantageous properties such as low thermal conductivity, enhanced thermal resistance, dimensional stability, low water uptake, and high compressive strength, growing remarkably upon thermal exposure.

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Section: Resultsmentioning

confidence: 99%

Chitosan Oligomer as a Raw Material for Obtaining Polyurethane Foams

Strzałka

Lubczak

2023

Polymers

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“…Hydroxyalkylation of cyclic monoimides has been exploited mostly for syntheses [1] [2] [3] [4]. Knowledge on the kinetics and mechanism of the reaction is limited to two publications [5] [6]. On the other hand the kinetics and mechanism of reaction of oxiranes with compounds containing acidic groups like alcohols, thiols, carboxylic acids, amides are well recognized [2] [7]- [13].…”

Section: Introductionmentioning

confidence: 99%

“…Encountered multifunctional cyclic imides are not suitable for monitoring the kinetics of reaction with oxiranes due to their low solubility in contrary to cyclic monoimides [5] [6]. The kinetics and mechanism of reaction between oxiranes (EO and PO) with SI, PI, and GI in presence of triethylamine (TEA) was studied in details and general rate low was found as [5]:…”

Section: Introductionmentioning

confidence: 99%

“…the reaction of N-(hydroxyalkyl)imides with oxiranes follow different mechanism than reaction of imide with oxirane. The oxirane-related order of consecutive reaction is 1 in comparison with ½ for reaction of imide with oxirane [5] [6]. In order to further understand the mechanism of these processes we have undertaken detailed study on kinetics of reaction between cyclic imides and oxiranes in presence of sodium hydroxide catalyst.…”

Section: Introductionmentioning

confidence: 99%

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Hydroxyalkylation of Cyclic Imides with Oxiranes Part III. Mechanism of the Reaction in Presence of Sodium Hydroxide Catalyst

Lubczak¹,

Lubczak²,

Naróg³

2018

OJPC

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The kinetics of reaction between cyclic monoimides (succinimide, phtalimide, and glutarimide) with ethylene and propylene oxides in presence of sodium hydroxide was studied. The effect of substrate and catalyst concentrations on the course of the reaction was investigated. Kinetics of reaction was studied by dilatometry, i.e. by measuring volume contraction of reaction mixture. The kinetic law describing the reaction of imides with oxiranes is: 1 2 1 2 cat AH B V kc c c =. where c cat , c AH and c B are concentrations of catalyst, imide, and oxirane, respectively. The relative reactivity of imides and oxiranes was: GI > PI ≥ SI and EO > PO. The reaction mechanism was proposed based upon experimentally determined rate law for the reaction of cyclic monoimides and oxiranes as well as analytical and instrumental analysis of products. The elementary reaction between oxirane and imide anion is rate determining step. The imide anion is formed by hydrogen cation transfer into catalytic hydroxide anion from dissociated NaOH. In the consecutive elemental reaction an imidate anion attack on the oxirane molecule occurs. It is the slowest stage of the reaction, limiting the entire process. All the studied reactions obey the same mechanism as can be concluded from isokinetic relationship of studied systems)

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“…Nowadays, however, there is a worldwide tendency to withdraw the antipirenes produced based on chlorine and bromine because of the high toxicity during their thermal decomposition. The addition of large amounts of antipirenes in order to obtain the desired non-flammable effect causes technological issues and significantly decreases the physicomechanical properties and dimensional stability of the produced materials [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Polyol Containing Boron Atoms as a Compound which Reduces Flammability of Rigid Polyurethane‐Polyisocyanurate Foams

Paciorek‐Sadowska¹

2017

Aspects of Polyurethanes

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The article presents results from multidisciplinary research conducted with the purpose of obtaining new material which reduces lammability and is used for the production of rigid polyurethane-polyisocyanurate foams (PUR-PIR). During the preparation of the foam recipe, special atention was paid to the ability to lower the lammability and the improvement of durability and thermo-insulation properties of rigid foams by using the new, non-halogen polyol. The new boron compound helped obtaining iresafe PUR-PIR foams, which are characterized by the reduced amount of total exhausted heat, longer time to full combustion, lower amount of produced carbon dioxide and oxide, increased oxygen index and lower maximum burning temperature in shorter time than the reference foam.

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Hydroxyalkylation of Cyclic Imides with Oxiranes. Part II. The Mechanism of Reaction in Presence of Triethylamine

Cited by 6 publications

References 9 publications

Chitosan Oligomer as a Raw Material for Obtaining Polyurethane Foams

Chitosan Oligomer as a Raw Material for Obtaining Polyurethane Foams

Hydroxyalkylation of Cyclic Imides with Oxiranes Part III. Mechanism of the Reaction in Presence of Sodium Hydroxide Catalyst

Polyol Containing Boron Atoms as a Compound which Reduces Flammability of Rigid Polyurethane‐Polyisocyanurate Foams

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