Salicyclic acid (45 g) and acetic acid (200 g) were heated to 80-90° C. in pre-reaction vessel and fed to the reactive

distillation column at 1 to 15 ml/min flow rate. Conversion of 80 to 99percent conversion is achieved. The column

bottom mass is fed to a distillation vessel where 50 to 100 ml of acetic acid is evaporated under vacuum. To dilute the

acid concentration in product mass, 100-200 ml of water is added to help better quality tech Aspirin. The diluted mass

is then cooled to 10-30° C., crystallized mass filtered to get the tech Aspirin. 200-500 ml of water and activated carbon

of 1-4percent of technical mass are added to technical material and temperature is raised to 70-95° C. and maintained

for 15-60 min. Activated carbon is filtered and mass is cooled to 5-30° C. over 5-10 hrs. Crystallized mass filtered to get

the pharma grade Aspirin with LOD of 5-8percent dried to <0.5percent LOD. The yield is achieved in the range of 1.05

to 1.15Tech ML and Pharma ML are concentrated to 40 to 90 wt percent solids by evaporation of acetic acid and water

mixture at 50-80° C. and >400 mm Hg vacuum. The concentrated mass cooled to 10-30° C., crystallized mass filtered.

This second crop Aspirin is further treated with charcoal (2-5percent of mass) with 2-4 times of water. Second crop yield

is in the range of 0.04 to 0.09. An Overall yield of this process obtained is in the range of 1.09 to 1.24. A percentage

yield of 83.5 to 95percent is obtained

Anhidrida acetica

Comparative Example 1In this comparative example, a batch process without adding the promoter of the present

invention was used, as a comparative experiment, to carry out the carbonylation reaction. The following constituents

with specified amounts were fed into the reactor: 50 wt. percent of methyl acetate, 25 wt. percent of methyl iodide, 5

wt. percent of acetic anhydride, lithium iodide (40000 ppm of Li ion), 800 ppm of the Rh catalyst, and an appropriately

balanced amount of acetic acid as a solvent. The reactor into which the mixture of the aforementioned reactants had

been fed was firstly pressurized with hydrogen to 1 kg/cm2, and then carbon monoxide was introduced into the reactor,followed by a gradual elevation of temperature. After the set temperature for the reaction was reached, carbon

monoxide was resupplied so that the inner pressure of the system reached 27 kg/cm2. During the reaction, carbonmonoxide kept on being resupplied with the consumption of carbon monoxide so that the pressure stably maintained

27 kg/cm2. The consumption of carbon oxide was recorded and a constituent analysis was carried out by sampling soas to calculate the unit space-time yield (STY) of acetic anhydride (unit: mole/liter*hour).; Examples 1214Influence of

Added Amount of Organic Promoters on Reaction RateThe carbonylation reactions were carried out under the same

conditions as the Comparative Example 1, except that 2 wt. percent, wt. percent and 6 wt. percent of organic

promoters, N-acetylimidazole, were added in the reaction media. The experimental results were recorded in Table 4. It

is obvious from Table 4 that the STY values of the carbonylation reaction were increased synchronously with the

increase in the added amount of organic promoter, which shows the carbonylation reaction rate can indeed be

satisfactorily increased by the increase in the added amount of these kinds of organic promoters according to the

present invention. In addition, when the Example 14 is compared with the Comparative Example 1, it is found that the

addition of these kinds of organic promoters can maintain the original reaction rate with the added amount of lithium

iodide reduced, which shows these kinds of organic promoters and lithium iodide have the same or even better effect of

stabilizing the catalyst. Another advantage is that the used amount of lithium iodide in the process can be reduced so

that the load of the deiodination process in the later stage can be reduced. TABLE 4 Influence of Added Amount of

Organic Promoters on Reaction Rate STY Content of Li+ value Organic Promoter Temp. Pressure (LiI) (gmol/ Reagents

(wt percent) (° C.)(kg/cm2) (ppm) L * hr) Compar. 190 27 4000 9.13 Example 1 Example 7 N-acetyl- 2 190 27 400010.78 Example imidazole 4 190 27 4000 11.33 12 Example 6 190 27 4000 12.06 13 Compar. 190 27 3000 8.22 Example

2 Example N-acetyl- 4 190 27 3000 10.96 14 imidazole

3.ii:EXAMPLE 13

(ii)

A mixture of 23.4 parts of the secondary amine described above, 8.0 parts of liquefied ethyleneoxide, 100 parts of

acetic acid and 100 parts of water is stirred in a closed vessel at room temperature for 5 hours.

The hydroxyethylated product STR47 recovered from the reaction mixture by the complete removal of solvent is then

acetylated by heating with 50 ml of acetic anhydride on boiling water-bath for 30 minutes. 32.0 Parts of the acetyl

derivative STR48 are then formylated according to the procedure described in example 6 and the formyl derivative

STR49 is hydrolyzed according to procedure used in example 6 to yield the salicylaldehyde derivative STR50 solution in

150 parts of chlorobenzene.

9.6:

This example illustrates the production of acetic anhydride (Ac2O) by the carbonylation of methyl acetate in the

presence of palladium and 1-butyl-3-methylimidazolium iodide. The reactor of Example 1 was loaded with

1-butyl-3-methylimidazolium iodide (14.45 g, 10 mL) and a mixture of palladium acetate (73.1 mg, 0.325 mmol)

dissolved in methyl acetate (3 mL). The reactor was pressurized to 200 psig (13.8 barg) with CO (20 SCCM) and heated

to 180° C. The gas feed was then changed to 150 SCCM CO and 8 SCCM hydrogen and a liquid feed consisting of

methyl acetate/acetic acid/methyl iodide in a weight ratio of 65/21/14 having a density=1.0 was fed at 0.13 mL/minute.

Examples 9-1,9-2, 9-3, and 9-4 were performed under these conditions. Example 9-5 was performed using the same

gas and liquid feed rates at a 190° C. furnace temperature. Example 9-6 was performed at 190° C. in the absence of

hydrogen with the carbon monoxide and liquid feed rates unchanged. The results are summarized in Table 11.