CN101225045A - Micro-wave synthetic method for preparing methyl salicylate - Google Patents

Abstract

The invention discloses a microwave synthetic preparation method for methyl salicylate, which is characterized in that: salicylic acid and methanol are used as raw material and concentrated sulfuric acid is used as catalyst; heating is made for reflux reaction under microwave radiation condition before separating to get salicylic acid methyl ester. The microwave synthetic preparation method for methyl salicylate has the advantages of greatly improving reaction ratio and shortening reaction time and significantly increasing reaction yield compared with normal preparation method for methyl salicylate.

Description

A kind of microwave synthesis method for preparing wintergreen oil

Technical field

The present invention relates to organic synthesis technology, especially, relate to a kind of microwave synthesis method for preparing wintergreen oil.

Background technology

Wintergreen oil formal name used at school Methyl Salicylate is colourless or red oily liquids.Because it is a leaves of purpurea distillation main body of oil, has Chinese ilex gas, so be commonly called as wintergreen oil.Wintergreen oil is a kind of broad-spectrum Chemicals, be mainly used in edible and makeup spices, as the essence of Tuberose, Acacia etc., the food flavour of strawberry, grape etc. also can be used for the solvent and the intermediate of sterilant, sterilant, anodyne, lustering agent and coating etc.Natural winter-green oil extract output is very limited, mainly adopts the industrial preparation wintergreen oil.The main method of present industrial salicylate methyl esters is: is catalyzer with the vitriol oil, Whitfield's ointment and methyl alcohol directly carried out esterification, still, and equipment complexity and seriously corroded, and routine adds thermal synthesis, general reaction times need 3-4 hour; Also useful now solid superacid as catalyst salicylate methyl esters, but do the aftertreatment more complicated of catalyzer with solid super-strong acid, and the preparation solid super-strong acid is more time-consuming, generally needs about a week, and synthesising reacting time needs 6-7 hour.

Summary of the invention

In order to overcome present known synthetic method long reaction time, equipment complexity, the loaded down with trivial details deficiency of aftertreatment, the purpose of this invention is to provide a kind of microwave synthesis method for preparing wintergreen oil, its equipment is simple, the thorough and time-saving energy-saving of chemical reaction.

The objective of the invention is to be achieved through the following technical solutions: a kind of microwave synthesis method for preparing wintergreen oil may further comprise the steps;

(1) the roundlet mouth place at microwave reactor top connects single port Glass tubing and spherical condensating tube, and ON cycle water;

(2) with mol ratio be 1: 5～1: 9 Whitfield's ointment and methyl alcohol stirring and dissolving, slowly add the vitriol oil, mixing solutions is poured in the special-purpose flask of microwave, put into microwave reactor;

(3) microwave power is controlled between 130～300 watts, carries out the microwave heating reaction, the reaction times is 10～40 minutes;

(4) microwave heating reaction postcooling adds distilled water and washes out oil reservoir, is clear until the upper strata;

(5) pour in the separating funnel and tell lower floor's oil reservoir after static, the sodium carbonate solution with 20% washs to pH=7;

(6) pour in the separating funnel behind the adding distilled water, tell lower floor's oil reservoir,, filter with this lower floor's oil reservoir of anhydrous magnesium sulfate drying;

(7) filtrate being done underpressure distillation, is 60～70 ℃ in temperature, and when pressure was 19.0～19.9mmHg, the collection colourless liquid was a wintergreen oil.

Further, the mol ratio of the Whitfield's ointment and the vitriol oil is 1: 0.4～1: 0.85.

The invention has the beneficial effects as follows:

1, the present invention adopts microwave salicylate methyl esters, and its equipment is simple, and clean environment firendly;

2, synthesising reacting time of the present invention was at 15-40 minute, and the reaction times shortens greatly;

3, power of the present invention is between 130-260, and its energy consumption is lower.

Specific implementation method

Describe the present invention below in detail, it is more obvious that purpose of the present invention and effect will become.

The present invention is under the condition that catalyzer exists, and the heating reflux reaction under the microwave radiation condition with Whitfield's ointment and methyl alcohol adopts ordinary method to separate then and obtains wintergreen oil.Catalyzer can be the vitriol oil.Microwave heating effect is a microwave radiation of utilizing 2450 hertz of frequencies, thereby the dipole that orders about in the reactant molecule is made vibration at high speed acquisition energy, reduces the activation energy of reaction.Adopt microwave heating, directly act on the body heat phase of target molecule, can finish the original position Conversion of energy and make the molecule instantaneously heating, thus microwave heating process not from the interface to the heat transfer process of body phase, uniform distribution of temperature field, thermo-efficiency height.According to the microwave heating that the present invention adopts, the conventional heating of speed of response improves a lot, and shortened the reaction times greatly, and yield significantly improves.

Implementation step:

1, at the roundlet mouth place at microwave reactor top, connect single port Glass tubing and spherical condensating tube, and ON cycle water.

2, with mol ratio be 1: 5～1: 9 Whitfield's ointment and methyl alcohol stirring and dissolving, slowly add the vitriol oil (mol ratio of the Whitfield's ointment and the vitriol oil is 1: 0.4～1: 0.85), mixing solutions is poured in the special-purpose flask of microwave, put into microwave reactor.

3, microwave power is controlled between 130～300 watts, carries out the microwave heating reaction.

4, the reaction times was controlled between 10～40 minutes.

5, after the cooling, liquid being poured in the 500mL beaker, added distilled water and wash out oil reservoir, is clear until the upper strata.

6, be poured in the separating funnel and tell lower floor's oil reservoir after static.Sodium carbonate solution with 20% washs to pH=7.

7, pour in the separating funnel behind the adding distilled water, tell lower floor's oil reservoir, use the anhydrous magnesium sulfate drying after-filtration.

8, filtrate being done underpressure distillation, is 60～70 ℃ in temperature, and when pressure was 19.0～19.9mmHg, the collection colourless liquid was a wintergreen oil.

Embodiment 1

12.0g Whitfield's ointment and 20.88g anhydrous methanol are poured in the there-necked flask after the heated and stirred dissolving in beaker, place it in then on the glass round platform in the microwave oven, the small sircle hole that passes the microwave oven top with a prolong docks with round-bottomed flask in the microwave oven by two mouthfuls of Glass tubings, the vitriol oil that slowly adds 3.0ml, keep refluxing, it is 195 watts that reaction power is set, and behind the radioreaction 25min, stops heating.After the cooling, liquid being poured in the beaker, added distilled water and wash out oil reservoir, is clear until the upper strata.Be poured into the static lower floor's oil reservoir of telling in the separating funnel.Sodium carbonate solution with 20% washs to pH=7.Pour in the separating funnel after adding distilled water, tell lower floor's oil reservoir.Use anhydrous magnesium sulfate drying.Behind the decompress filter filtrate being done underpressure distillation, is 60-70 ℃ in temperature, and when pressure was 19.9mmHg, the collection colourless liquid was a wintergreen oil, gets product wintergreen oil 11.30g, productive rate 85.5%.

The foregoing description is used for the present invention that explains, rather than limits the invention, and in the protection domain of spirit of the present invention and claim, any modification and change to the present invention makes all fall into protection scope of the present invention.

Claims (2)

1. a microwave synthesis method for preparing wintergreen oil is characterized in that, may further comprise the steps;

(1) at the roundlet mouth place at microwave reactor top, connect single port Glass tubing and spherical condensating tube, and ON cycle water.

(2) with mol ratio be 1: 5～1: 9 Whitfield's ointment and methyl alcohol stirring and dissolving, slowly add the vitriol oil, mixing solutions is poured in the special-purpose flask of microwave, put into microwave reactor.

(3) microwave power is controlled between 130～300 watts, carries out the microwave heating reaction, the reaction times is 10～40 minutes.

(4) microwave heating reaction postcooling adds distilled water and washes out oil reservoir, is clear until the upper strata.

(5) pour in the separating funnel and tell lower floor's oil reservoir after static, the sodium carbonate solution with 20% washs to pH=7.

(6) pour in the separating funnel behind the adding distilled water, tell lower floor's oil reservoir,, filter with this lower floor's oil reservoir of anhydrous magnesium sulfate drying.

(7) filtrate being done underpressure distillation, is 60～70 ℃ in temperature, and when pressure was 19.0～19.9mmHg, the collection colourless liquid was a wintergreen oil.

2. the microwave synthesis method of preparation wintergreen oil according to claim 1 is characterized in that, the mol ratio of the Whitfield's ointment and the vitriol oil is 1: 0.4～1: 0.85.