2,2-Dimethoxyacetaldehyde

To a suspension of NaIOIn a 1000mL reaction flask with mechanical stirring and a thermometer was added 1, 1, 4, 4-tetramethoxy-2-butene compound 70g and 500mL dimethylsulfide. Place in -10 deg.C conditions, the replacement of the bottle after the air into nitrogen, to a closed reaction system was slowly injected ozone 30g, to control the reaction temperature was maintained at -10 deg.C, reaction 10h after completion of the reaction raw materials, warmed to room temperature, the solvent was evaporated to give the compound 1, 1-dimethoxy acetaldehyde 29g.In 1000 mL of a reaction flask equipped with a mechanical stirrer and a thermometerCompound 1, 1, 4, 4-tetramethoxy-2-butene (70 g) and methyl sulfide (500 mL)Placed at -10 ° C, Replace the bottle after the air into the nitrogen, To the closed reaction system slowly into the ozone 30g, Control the reaction temperature at -10 ° C, After 10 hours of reaction, the reaction reaction was complete and the temperature was raised to room temperature. After the solvent was distilled off, the compound 1, 1-dimethoxyacetaldehyde (32 g) was obtained.In eine beheizbare 1m-Kolonne (Durchmesser 29mm) mit Drahtgeflechteinsaetzen wurde am Kopf eine waessrige Glyoxal-Loesung (40 Gew.-percent), die mit einer kleinen Menge einer Loesung von p-Toluolsulfonsaeure in Methanol versetzt wurde, ueber eine Pumpe eindosiert. Gleichzeitig wurde am untersten Boden der Kolonne gasfoermiges Methanol eingespeist. Am Kopf der Kolonne wurde ein Destillat-Gemisch aus Wasser und Methanol aufgefangen, am Sumpfablauf wurde ein Gemisch aus 1, 1, 2, 2-Tetramethoxyethan, 2, 2-Dimethoxyacetaldehyd und Methanol aufgefangen. Das Kopfdestillat, bestehend aus Wasser und Methanol, wurde an einer weiteren Kolonne aufdestilliert, wobei das Methanol zurueckgefuehrt, wieder verdampft und in den untersten Eintritt der Kolonne eingespeist wurde. Die Rueckgewinnung des Methanols kann ebenfalls an der Reaktionskolonne geschehen, wenn oberhalb der Dosierstelle der Glyoxal-Loesung noch eine weiter Kolonne, die ueber einen Seitenabzug verfuegt, eingesetzt wird. Das ablaufende Gemisch bestehend aus 1, 1, 2, 2-Tetramethoxyethan (TME), 2, 2-Dimethoxyacetaldehyd und Methanol wurde ebenfalls an einer weiteren Kolonne destillativ aufgearbeitet, wobei die leichtersiedenden Komponenten Methanol und 2, 2-Dimethoxyacetaldehyd in den Prozess zurueckgefuehrt wurden. Methanol wurde wiederum verdampft und am Boden der Kolonne eingespeist, 2, 2-Dimethoxyacetaldehyd konnte der waessrigen Glyoxal-Loesung zugegeben und mit dieser am Kopf der Kolonne eingespeist werden. Die Glyoxal- und Methanol-Dosierung wurde so gewaehlt, dass Verhaeltnisse von Glyoxal zu Methanol von 1 mol : 4 mol bis zu 1 mol : 18 mol vorlagen. Die Kolonne wurde entweder unbeheizt gefahren oder bis zu einer Temperatur von 160 °C beheizt. Die folgende Tabelle gibt die Ergebnisse unterschiedlicher Fahrweisen wieder: [] NrVerhaeltnis Glyoxal : MeOH [mol : mol]Temp. [°C]Dosierung Glyoxal [mol/h]Reaktionszeit [h]Ausbeute TME [g (percent)]11 : 4900, 178112(55percent)21 : 8900, 178138(68percent)31 : 121000, 464226 (82 percent)41 : 12900, 258276 (92 percent)51 : 181000, 178161 (79percent)61 : 18900, 178169(83percent)In einem 4-1-Vierhalskolben mit Tropftrichter, Ruehrer und einer Kolonne, bei der Destillat ueber Kopf und ueber einen Seitenabzug entnommen werden konnte, wurden 100 g Methanol, 1 269 g (8, 74 mol) einer 40 percentigen waessrigen Glyoxal-Loesung und 70 g p-Toluolsulfonsaeure vorgelegt. Aus diesem Ansatz wurde derart ein Gemisch aus Wasser und Methanol abdestilliert, dass ueber den Seitenabzug der Kolonne Wasser und Methanol und ueber Kopf reines Methanol entnommen wurde, welches dem Sumpf wieder zugefuehrt wurde. Die ueber den Seitenabzug entfernte Methanolmenge wurde per Gaschromatographie bestimmt und im Sumpf durch frisches Methanol ersetzt. Nach einer Reaktionszeit von 11 Stunden liess sich im Sumpf die Bildung eines Gemisches bestehend aus 12, 1 percent 1, 1, 2, 2-Tetramethoxyethan, 2, 2-Dimethoxyacetaldehyd, Wasser, Methanol und einiger hochsiedender Komponenten nachweisen. Aus diesem Gemisch liessen sich destillativ 126 g 1, 1, 2, 2-Tetramethoxyethan isolieren (0, 84mol, 10 percent).[0037] An aqueous glyoxal solution (40percent by weight) which had been admixed with a small amount of a solution of p-toluenesulfonic acid in methanol was metered using a pump into the top of a heatable 1 m column (diameter 29 mm) with wire braid inserts. At the same time, gaseous methanol was fed in at the lowermost tray of the column. At the top of the column, a distillate mixture of water and methanol was collected, and a mixture of 1, 1, 2, 2-tetramethoxyethane, 2, 2-dimethoxyacetaldehyde and methanol was collected at the bottom discharge. The top distillate consisting of water and methanol was distilled in a further column, and the methanol was recycled, reevaporated and fed into the lowermost inlet of the column. The methanol can likewise be recovered in the reaction column when a further column which had a stream above the metering point of the glyoxal solution is used. The effluent mixture consisting of 1, 1, 2, 2-tetramethoxyethane (TME), 2, 2-dimethoxyacetaldehyde and methanol was likewise worked up by distillation in a further column, and the lower-boiling components methanol and 2, 2-dimethoxyacetaldehyde were recycled into the process. Methanol was again evaporated and and fed in at the bottom of the column, and 2, 2-dimethoxyacetaldehyde could be added to the aqueous glyoxal solution and fed in with it at the top of the column. The glyoxal and methanol were metered in at such a rate that the mole ratios of glyoxal to methanol present were from 1:4 mol up to 1:18. The column was either operated unheated or heated up to a temperature of 160° C.[0038] The apparatus described under was operated in such a way that 174 g of a mixture which consisted of 1.16 mol of glyoxal, 0.04 mol of 2, 2-dimethoxyacetaldehyde, a small amount of p-toluenesulfonic acid and also of methanol and water were metered in at the top of the column. At the same time, gaseous methanol was introduced at the bottom of the column. The column was heated. On completion of metering, the bottom effluent was neutralized and worked up by means of vacuum distillation. 162 g (1.08 mol, 90percent based on glyoxal and 2, 2-dimethoxyacetaldehyde) of 1, 1, 2, 2-tetramethoxyethane were isolated.[0042] A 4 L four-neck flask equipped with dropping funnel, stirrer and a column in which the distillate could be removed via the top and via a sidestream was initially charged with 100 g of methanol, 1269 g (8.74 mol) of a 40percent aqueous glyoxal solution and 70 g of p-toluenesulfonic acid. A mixture of water and methanol was distilled out of this mixture in such a way that water and methanol were withdrawn via the sidestream of the column and pure methanol was withdrawn overhead and fed back to the bottom. The amount of methanol withdrawn via the sidestream was determined by gas chromatography and replaced at the bottom by fresh methanol. After a reaction time of 11 hours, the formation of a mixture in the bottom consisting of 12.1percent of 1, 1, 2, 2-tetramethoxyethane, 2, 2-dimethoxyacetaldehyde, water, methanol and some high-boiling components could be detected. It was possible to isolate 126 g of 1, 1, 2, 2-tetramethoxyethane (0.84 mol, 10percent) from this mixture by distillation.[0041] A 40percent aqueous glyoxal solution was metered at a rate of 0.17 mol/h into the top of a heatable 1 m column (diameter 29 mm) filled with spheres of diameter 5 mm of the catalyst KA-3 (Sud-Chemie). At the same time, gaseous methanol was metered in at the bottom of the column. During the entire reaction, the apparatus was operated under nitrogen as a protective gas. The column was heated. A mixture of water and methanol was collected at the top of the column. The bottom effluent of the column consisted of a mixture of 1, 1, 2, 2-tetramethoxyethane, 2, 2-dimethoxyacetaldehyde, methyl 2-hydroxyacetate, 2-hydroxyacetic acid and methanol. The apparatus was operated for 4 hours, and the bottom effluent was analyzed by gas chromatography. According to the analysis, there were 11 g (0.07 mol, 11percent) of 1, 1, 2, 2-tetramethoxyethane.

Molecular Weight:104.10
XLogP3:-0.4
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:3
Exact Mass:104.047344113
Monoisotopic Mass:104.047344113
Topological Polar Surface Area:35.5
Heavy Atom Count:7
Complexity:48.9
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes