CONDENSACION ALDOLICA PDF

Mechanism[ edit ] This section needs expansion with: actually discuss the dehydration mechanisms, not just present an image of them. You can help by adding to it. June The first part of this reaction is an aldol reaction , the second part a dehydration—an elimination reaction Involves removal of a water molecule or an alcohol molecule. Dehydration may be accompanied by decarboxylation when an activated carboxyl group is present. The aldol addition product can be dehydrated via two mechanisms; a strong base like potassium t-butoxide , potassium hydroxide or sodium hydride in an enolate mechanism, [13] [14] or in an acid-catalyzed enol mechanism.

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Gucage Ejemplo comparativo 3 Comparative Example 3. The first stage aldol condensation and the second stage crossed Cannizzaro reaction are usually conducted successively in the same reaction vessel, without differentiating from the operational point of view one another. Then, after further adding In the present invention, as described above, after first removing the inorganic salt such as sodium formate, and the component of high boiling the crude TMP, the treated TMP is subjected to heat treatment under acidic conditions.

In the present invention, as the load of distillation column is reduced, the distillation apparatus improved from the economic viewpoint with respect to the cruzxda and operatively allowing it to produce a highly pure TMP advantageously in industrial scale. In the present invention, it is not necessary cobdensacion use expensive cation exchange resins, etc. The Japanese Patent Publication No. Formaldehyde used in the present invention as starting material can be used as an aqueous solution or solid as paraformaldehyde.

The purity of TMP obtained was With such heat treatment, the component hardly removable from TMP by distillation is thermally decomposed or chemically combines to cruzaca an easily removable component of TMP by distillation. Such an acid may include mineral acids such as phosphoric acid and sulfuric acid and organic acids such as conednsacion acid and methanesulfonic acid. TMP obtained by the reaction between NBAL and formaldehyde in the presence of basic catalyst in the two-stage process of the aldol condensation and the subsequent crossed Cannizzaro reaction contains the impurities hardly removable by distillation.

After removing the unreacted formaldehyde, the reaction mixture was extracted with methyl ethyl ketone to obtain g of crude TMP containing 1. The solvent for the extraction may include ketones such as methyl ethyl ketone and methyl isobutyl ketone, aldehydes such as NBAL, also serving as material of alcohols such as isobutyl alcohol and isopropyl alcohol, and esters such as butyl acetate starting, and are typically used in a total amount of 0.

To minimize the occurrence of byproducts and increase selectivity of the objective TMP, preferred set the amount of the basic catalyst according to the reaction conditions. Purification of propylene oxide using an aqueous acetone extractive distillatin agent. However, when TMP contains the formic acid salt and the component of high boiling condensation products are decomposed hard by heat treatment in the presence of acid even in an amount equivalent to condnesacion amount of formic acid saltleaving obtained this a highly pure TMP mode.

The content of the remaining formaldehyde in the final TMP was 30 ppm. Recientemente, el TMP ha empezado a ser ampliamente utilizado y particularmente en ladolica uso como materia prima para resinas curables con ultravioleta, presentando el TMP una pureza superior a la que antes se ha llegado a requerir.

The aldol condensation and the subsequent crossed Cannizzaro reaction may be carried out in the presence of water in an amount of 2 to 20 times by weight of NBAL. In addition, formaldehyde remaining in TMP aldplica is not the completely eliminated by a usual distillation. Ejemplo comparativo 4 Comparative Example 4. In addition, a highly pure TMP is obtained, since the remaining formaldehyde condenses with TMP is to form easily removable CMF during one heat treatment under acidic conditions.

EST3 — Tucked to produce highly pure trimethylolpropane. Method for producing a trimethylolpropane TMP highly pure comprising the steps of: The reaction was complete after 0. Por tanto, se produce a escala industrial de manera ventajosa un TMP sumamente puro utilizable como materia prima para resinas curables con ultravioleta.

To completely remove the impurities such as formaldehyde, MDF, etc. The liquid reaction mixture from the two-stage process contains a formic acid salt apdolica during the crossed Cannizzaro reaction. It is known that the condensation products condenscion above are thermally decomposed under acidic conditions publication of Japanese Patent No.

The molar ratio of formaldehyde to be used in the method with NBAL is 3. The present invention has been accomplished based on this finding. Therefore it occurs industrially advantageously a highly pure TMP usable as a raw material for ultraviolet curable resins. Process for separating alcohols from mixtures of alcohols, water and other compounds. Masters and doctoral program in Chemical Sciences The content of the remaining formaldehyde in the final TMP was 3 ppm.

A process for obtaining trimethylolpropane-enriched product streams from the secondary streams of trimethylolpropane. These basic catalysts may be used alone or in combination of two or more. Method for producing a highly pure trimethylolpropane according to claim 1, wherein component removing high boiling point and the inorganic salt is carried out after deactivating sodium formate present in the crude trimethylolpropane, wherein the deactivation is carried out by means of adding an acid to crude TMP in an amount 0.

Particularly, MDF, which is quite difficult to remove by normal distillation becomes easily removable components by the treatment of the invention, thus enabling to obtain a highly pure TMP. As a result of extensive studies in the production method of TMP to eliminate the above problems, the inventors have found that a highly pure TMP is obtained from a crude TMP by previously removing a component of high boiling point and an inorganic salt such as sodium formate, the crude TMP, heat-treating the treated TMP under acidic conditions, and purifying the heat-treated TMP by distillation, etc.

Method for producing highly pure trimethylolpropane. The present invention relates to a method of purifying a crude TMP obtained by an aldol condensation and a subsequent crossed Cannizzaro reaction of NBAL of formaldehyde in the presence of a basic catalyst.

The product mixture from the reaction of NBAL and formaldehyde is separated, if necessary after removing formaldehyde unreacted by condensation in crude TMP and the formic acid salt, obtained as a byproduct during the crossed Cannizzaro reaction by a solvent extraction or hot filtration after condensing. The content of the remaining formaldehyde in the final TMP was 1 ppm. For example, the two-phase process using sodium hydroxide is expressed by the following reaction scheme.

Without adding phosphoric acid and without subjecting to heat treatment, g of the distillate mainly comprising TMP by distillation at under a reduced pressure of Pa 1 Torr using a column with Sulzer-packed 10 theoretical stages purified.

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