Study of the reaction between resorcinol and formaldehyde

doi:10.1016/0032-3861(81)90019-7

Polymer

Volume 22, Issue 6, June 1981, Pages 804-806

https://doi.org/10.1016/0032-3861(81)90019-7 Get rights and content

Abstract

The reactions between resorcinol and formaldehyde were led in aluminium pans of a d.s.c. Perkin Elmer calorimeter. The products were separated by means of high performance liquid chromatography and identified by ¹H and ¹³C n.m.r. Depending on the catalyst concentration and molar ratio the mixtures reacted at two different temperature ranges, 317–332K and 332–366K. The heat of the reaction in the first temperature range was between 16.8 and 45.0 kJ mol⁻¹ for molar ratios 1:1 and 1:3 respectively. By ¹H and ¹³C n.m.r. spectroscopy five addition products were determined. The reaction heat in the second temperature range was 73.5 kJ mol⁻¹ and was attributed to condensation reactions. The activation energies were 95.0 and 120.0 kJ mol⁻¹ for addition and condensation reactions respectively. For addition, order two and for condensation, order one of reaction was established. On the basis of these foundings tentative reaction schemes were prepared.

References (8)

A. Šebenik et al.
Eur. Polym. J.
(1974)
G.D. Harlampovich et al.
Fenoly, Izdatel stvo
(1974)
R.E. Majors
Anal. Chem.
(1971)
A.A. Zavitsas et al.
J. Polym. Sci.
(1968)

There are more references available in the full text version of this article.

Cited by (27)

Geometry-based cross-linking algorithm for modeling resorcinol resins through united-atom molecular dynamics simulations
2024, Polymer
The addition-condensation polymerization (ACP) of resorcinol with formaldehyde and the electrochemical polymerization (ECP) of resorcinol were desirable to improve the performances of resins. To achieve computational design, a new geometry-based cross-linking modeling algorithm for three-dimensional (3D) cross-linked network structures of resorcinol resins was developed for molecular dynamics (MD) simulations using a united-atom model. The ACP and ECP of resorcinol were successfully modeled using one algorithm by changing the parameters of the reaction rate constants of methylene, ether, and biphenyl bond formations. Furthermore, reaction judgment was performed under a reaction probability function comprising the Gaussian functions based on the interatomic distance of the reaction candidate atom pairs and interior angles regarding the spatial arrangement of two resorcinol rings. This geometry-based cross-linking algorithm successfully generated strainless 3D cross-linked network structures of the ACP and ECP resorcinol resins without the formation of highly bent unstable structures, such as U-shaped biphenyls. The MD simulation results indicated that the cross-linking of the ACP resin comprising methylene linkages proceeded with a network structure formation mechanism similar to that of phenolic resins, where the cross-linked network structure was determined at the gel point and the reactions after the gel point were to fix and freeze the network structure. For the ECP resins comprising ether and biphenyl linkages, the molar ratio of ether to biphenyl bonds affected the elastic property of the resins, and the incorporation of rigid biphenyl structures into ether-linkage networks increased the elastic modulus. Moreover, an increase in rigidity was observed as a decrease in the Poisson's ratio.
On the synthesis and structure of resorcinol-formaldehyde polymeric networks - Precursors to 3D-carbon macroassemblies
2015, Polymer
Citation Excerpt :
While over the last 40 years there has been a concerted effort to define mechanisms and kinetic dependences of inorganic sol–gel processes [15–18], there has been much less progress in understanding organic, sol–gel reactions. There are a number of publications on the early stage reaction mechanisms of the RF reaction [19–22], however the mechanisms proposed are general (see Fig. 1), make large assumptions about the purity and state of the starting material and provide virtually no information on the kinetics of the network formation process. With new impetus towards the development of hierarchical graphene and CNT macro-assemblies for application in fields such as advanced energy storage and catalysis, there is much renewed interest in the organic sol–gel process.
With the new impetus towards the development of hierarchical graphene and CNT macro-assemblies for application in fields such as advanced energy storage, catalysis and electronics; there is much renewed interest in organic carbon-based sol–gel processes as a synthetically convenient and versatile means of forming three dimensional, covalently bonded organic/inorganic networks. Such matrices can act as highly effective precursors, scaffolds or molecular ‘glues’ for the assembly of a wide variety of functional carbon macro-assemblies. However, despite the utility and broad use of organic sol–gel processes – such as the ubiquitous resorcinol-formaldehyde (RF) reaction, there are details of the reaction chemistries of these important sol–gel processes that remain poorly understood at present. It is therefore both timely and necessary to examine these reactions in more detail using modern analytical techniques in order to gain a more rigorous understanding of the mechanisms by which these organic networks form. The goal of such studies is to obtain improved and rational control over the organic network structure, in order to better direct and tailor the architecture of the final inorganic carbon matrix. In this study we have investigated in detail, the mechanism of the organic sol–gel network forming reaction of resorcinol and formaldehyde from a structural and kinetic standpoint, by using a combination of real-time high field solution state nuclear magnetic resonance (NMR), low field NMR relaxometry and differential scanning calorimetry (DSC). These investigations have allowed us to track the network formation processes in real-time, gain both detailed structural information on the mechanisms of the RF sol–gel process and a quantitative assessment of the kinetics of the global network formation process. It has been shown that the mechanism, by which the RF organic network forms, proceeds via an initial exothermic step correlated to the formation of a free aromatic aldehyde. The network growth reaction then proceeds in a statistical manner following a first order Arrhenius type kinetic relationship – characteristic of a typical thermoset network poly-condensation process. And despite the relative complexity and ill-defined nature of the formaldehyde staring material, the final network structure is to a large extent, governed by the substitution pattern of the resorcinol molecule.
A two-step synthesis of ordered mesoporous resorcinol-formaldehyde polymer and carbon
2012, Carbon
Citation Excerpt :
It has been suggested that the rate determining step under acidic conditions is the addition reaction [33,34]. However, under the presence of a base catalyst, resorcinol can react with formaldehyde rapidly at low temperatures (preferably room temperature or lower) to produce the hydroxymethyl compounds, but the condensation reaction between the hydroxymethyl compounds is slow relative to the addition reaction [35,36]. So if the reaction of resorcinol and formaldehyde is catalyzed by a base in the first step and then the condensation reaction is catalyzed by an acid in the second step, it is expected that highly cross-linked polymers can be obtained rapidly.
A new two-step method is developed for the synthesis of resorcinol–formaldehyde polymer and carbon with highly ordered mesoporous structures. For this method, resorcinol and formaldehyde is pre-polymerized in the first step under the presence of a basic catalyst to produce resorcinol–formaldehyde resol. Then, the resorcinol–formaldehyde resol is mixed with Pluronic F127 solution followed by the addition of an acid catalyst to allow the rapid self-assembly and condensation in the second step. Compared with the early reported evaporation-induced self-assembly method as well as the one-step liquid phase self-assembly method, in the present two-step liquid method the self-assembly and condensation process can be carried out rapidly by using low amount of base and acid catalysts at room temperature. After the activation by CO₂, the carbon materials maintained ordered mesostructure, and the BET surface area enlarged to 2660 m²/g and total pore volume increased to 2.01 cm³/g. The CO₂ activation not only creates micropores within the carbon frameworks but also enlarges the mesopores by elimination of the carbon pore walls.
Calorimetric analysis of the polymerization reaction of a phenolic resin
1995, Thermochimica Acta
The polymerization of a phenolic resole resin, used as a matrix for glass-fiber-reinforced composite materials, was studied using differential scanning calorimetry (DSC), and a kinetic model of the complex reactive process was developed. Two distinguishable reaction peaks were obtained in the dynamic DSC thermograms and were assigned to two independent cure reactions characterized by different activation energies. The kinetic analysis, performed by regression analysis on several DSC scans obtained at different heating rates, led to the determination of kinetic constants, activation energies and reaction orders for the two different kinetic equations. Both equations were integrated in a general model of the cure process through the inclusion of a weighting factor representing the fraction of heat developed in each reaction. Good agreement between experimental and modeling results was obtained.
Aerogels derived from multifunctional organic monomers
1992, Journal of Non-Crystalline Solids
The ability to tailor the structure and properties of aerogels at the nanometer scale opens exciting possibilities for these novel materials. Traditional inorganic aerogels are made via the hydrolysis and condensation of metal alkoxides. Synthesis of organic aerogels based upon the aqueous polycondensation of (1) resorcinol with formaldehyde and (2) melamine with formaldehyde was recently reported. The former materials can also be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. In both the inorganic and organic systems, the structure and properties of the dried aerogel are dictated by polymerization conditions. Factors such as pH, reactant ratio, and temperature influence the cross-linking chemistry and growth processes taking place prior to gelation. This paper addresses the chemistry-structure-property relationships of organic aerogels.
Organic aerogels: microstructural dependence of mechanical properties in compression
1990, Journal of Non-Crystalline Solids
Aerogels are a unique class of ultrafine cell size (<1000 Å), low-density foams. These materials have continuous porosity and a microstructure composed of interconnected colloidal-like particles or chains with characteristic diameters of 100 Å. Traditional aerogels are inorganic, made via the hydrolysis and condensation of metal alkoxides (e.g. tetraisopropoxy titanate). Recently, the authors reported the development of organic aerogels from the sol-gel polymerization of resorcinol with formaldehyde. Because these new aerogels are composed of a highly crosslinked aromatic polymer, they can be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. This work describes how the microstructure of these organic aerogels can be manipulated and controlled. The microstructural dependence of the compressive mechanical properties of both resorcinol-formaldehyde and carbon aerogels is examined in detail.

View all citing articles on Scopus

^☆: Part of this paper was reported at the IUPAC, International Symposium on Macromolecules, Mainz 1979.

View full text

Polymer paperStudy of the reaction between resorcinol and formaldehyde☆

Abstract

Eur. Polym. J.

Fenoly, Izdatel stvo

Anal. Chem.

J. Polym. Sci.

Polymer paper
Study of the reaction between resorcinol and formaldehyde☆