Estimating Kinetic Parameters for the Spontaneous Polymerization of Glycidol at Elevated Temperatures

Abstract

The ring-opening polymerization of glycidol at elevated temperatures is investigated. To improve the synthesis of dendritic polyether polyols, experiments are carried out without initiator to identify the influence of thermal side reactions. This results in a step-growth polymerization caused by the spontaneous combination of monomers. Kinetic parameters of the side reactions are estimated by fitting simulated number-and weight-average molecular weights to the experimental values measured at different reaction times during the polymerization. The reactions are conducted at three different temperatures of 90, 105, and 120 8C. It is shown that thermal side reactions lead to high dispersities of the final product and are highly sensitive to the reactor operating temperature.Scheme 2. Ring-opening reaction scheme for two glycidol monomers forming an AB 2 dimer (glycidly glycerine). By binding more monomers a dendritic polymer AB n (e.g., n ¼ 6) is created.Scheme 3. A typical cyclization reaction. The smallest cycle that can be formed is illustrated here.

Preparation of Functionalized Carbon‐Coated Cobalt Nanoparticles with Sulfonated Arene Derivatives, a Study on Surface Functionalization and Stability

“…In contrast, naphthalene sulfonica cid functionalizedn anoparticle 7,w ithout ap ossibility to initiate the anionic ROP of glycidol, as no hydroxyl group or other initiator site is available, showed only little increase in carbon content, which may be attributed to adsorption of spontaneous oligomerized glycidol. [29] This further supportsasurface polymerization process on the naphthol sulfonate functionalized particles 12.H owever,t he same reactionp erformed with the phenol sulfonate functionalized nanoparticle 11,y ielded an increaseo fo nly 0.47 wt %c arbon content,w hich is in as imilar range of the naphthalene sulfonate functionalized particles and therefore suggestso nly adsorption of oligomerized glycidola nd no surface polymerization. The inability to polymerize glycidol onto 11 may be due to the closer proximity of the sulfonate group or the smaller aromatic system, which may be overloaded due to too many substituents on the phenyl aromate in comparison to the naphthalene system.…”

Low molecular weight glycerol derived coatings on magnetic nanoparticles: role of initiator, temperature, rate of monomer addition, enhanced biocompatibility and stability

“…This leads to the conclusion that the monomer needs activation energy to be in a state to be able to react and at high temperatures, competitive side reactions may occur, that deplete the glycidol and reduce maximal loading on the particle. As can be seen by an article of Weiss et al , 23 it is possible for the spontaneous oligomerization of glycidol at elevated temperatures due to self-activation by hydrogen bonds from the alcohol towards the oxirane. Therefore, two possible polymerization reactions may occur in the investigated homogeneous reaction media.…”

Polyester-Based, Biodegradable Core-Multishell Nanocarriers for the Transport of Hydrophobic Drugs

“…The ring-opening reactions can be catalyzed under acidic or basic conditions, but can also take place at high temperatures initiated by any weak nucleophile. The latter case is called thermally-induced, ring-opening reaction of glycidol [ 22 ]. Based on the above-mentioned literature, we hypothesized that DBTL as Lewis acid mediates a ring-opening of glycidol initiated by carboxylic acid of hyperbranched polyesters.…”