Preparation method of acetylsalicylic acid
A technology of acetylsalicylic acid and salicylic acid, which is applied in the chemical industry, can solve the problems of troublesome catalyst preparation and expensive rare earth, and achieve the effects of low cost, simple method and increased yield
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Embodiment 1
[0018] Take 3.0g of salicylic acid and 1.0g of citric acid, react at 70°C for 30min, change the molar ratio of acid anhydride to investigate the influence of the molar ratio of acid anhydride on the product yield, the results are shown in Table 1 and figure 1 .
[0019] Table 1 The influence of the amount ratio of acid anhydride substances on the product yield
[0020] .
[0021] Depend on figure 1 And table 1 shows: along with the amount ratio of acid anhydride substance increases, salicylic acid fully acylates, and product yield increases; After reaching a certain ratio, along with the amount ratio of acid anhydride substance increases, because part product dissolves in In acetic anhydride, resulting in a decrease in yield. The optimum molar ratio of acid anhydride is 1:3.
Embodiment 2
[0023] The molar ratio of acid anhydride was 1:3, among them, 3.0g of salicylic acid was reacted at 70°C for 30min, and the amount of catalyst citric acid was changed to investigate the influence of the amount of catalyst citric acid on the product yield. The results are shown in Table 2 and figure 2 .
[0024] Table 2 Effect of catalyst dosage on aspirin yield
[0025] .
[0026] Depend on figure 2 It can be seen from Table 2 that with the increase of the amount of catalyst, the product yield increases, and reaches the maximum value after a certain amount, but the product yield decreases instead, which is caused by the participation of citric acid in the reaction. Therefore, citric acid is the best The dosage is 1.0g.
Embodiment 3
[0028] The molar ratio of acid anhydrides is 1:3, among them, salicylic acid is 3.0g, citric acid is 1.0g, the temperature is 75°C, and the reaction time is changed to investigate the influence of reaction time on the product yield. The results are shown in Table 3 and image 3 .
[0029] Table 3 Effect of reaction time on product yield
[0030] .
[0031] as table 3 and image 3 Shown:, reaction time is too short, and reactant is not reacted completely, and product yield is low; Reaction time is long, may by product increase, so product yield is also low, and optimal reaction time is 40min.
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