| 95% |
In methanol |
6 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 6 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol The target molecule was synthesised using similar procedure as described in Example 5 with D-sorbitol (36.4 g, 200 mmol), 3,4-dimethylbenzaldehyde (53.7 g, 400 mmol), and bismuth triflate hydrate (0.1 g, 0.15 mmol) in methanol (400 mL). After the same purification procedure as described in Example 5, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (78.7 g, 95%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
| 92% |
In methanol |
9 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 9 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol The target molecule was synthesised using similar procedure as described in Example 5 with D-sorbitol (9.11 g, 50 mmol), 3,4-dimethylbenzaldehyde (13.4 g, 100 mmol), and p-toluensulfonic acid monohydrate (1.4 g, 7.5 mmol) in methanol (100 mL). After the same purification procedure as described in Example 5, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (19.0 g, 92%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
| 90.3% |
Stage #1: 3,4-dimethylbenzaldehyde; D-sorbitol With camphor-10-sulfonic acid In methanol at 20℃; for 48h;
Stage #2: With methanol; sodium tetrahydroborate for 2h; |
7 Example 7 Preparation of a composition comprising pure 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol and organosilane treated fume silica powders
Example 7 Preparation of a composition comprising pure 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol and organosilane treated fume silica powders (0060) A 10 L four-necked cylindrical shaped reaction flask equipped with a thermometer, a nitrogen inlet, and a mechanical stirrer was charged with D-sorbitol (400 g, 2.20 moles), camphorsulfonic acid (12 g), 3,4-dimethyl-benzaldehyde (530 g, 3.95 moles) and methanol (4250 g), and then reacted at room temperature for 48 hours, so as to form a first reaction mixture. (0061) After neutralizing the first reaction mixture to pH 8, VenPure, 20 grams of sodium borohydride solution having 12% of NaBH4 effective amount, and 10.6 grams of an organosilane treated fume silica, CAB-O-SIL TS720, were added gently in the first reaction mixture and stirred for 2 hours to form a precipitated product. The precipitated product was washed with a 40 wt% methanol solution to obtain a second reaction mixture. (0062) Finally, a solid substance was collected by filtration, dried and ground to give a composition (748.9 g) as white dispersive powders having 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol and organosilane treated fume silica powders having a yield of 90.3%, an ash content of 1.3 % and a LC purity of 99.9%. No 3,4-dimethyl-benzaldehyde was detected by the GC analysis, and the composition did not release any odor. |
| 86.7% |
With methanesulfonic acid In methanol at 20℃; for 42h; Inert atmosphere; Large scale; |
2; 3; 4; 5; 6 Example 2
General procedure: In the instant example, a powdery diacetal clarifying agent of 1,3:2,4-di(3,4-dimethyl-benzylidene)-D-sorbitol was prepared through the following steps. (0162) (a) An 80 L small reaction flask equipped with a thermometer, a nitrogen inlet, and a mechanical stirrer was charged with D-sorbitol (4000 grams, 22 moles), methanesulfonic acid (100 grams), 3,4-dimethyl benzaldehyde (5300 grams, 39.5 moles), and methanol (40 L) and then reacted at room temperature for 42 hours, so as to form a first reaction mixture. (0163) (b) The first reaction mixture was filtered to remove the mother liquor, and added with new 20 L of methanol. Subsequently, 12% of potassium borohydride solution (200 grams) and Ultramarine Blue (1.28 grams) were slowly added into the first reaction mixture and stirred for 1 hour to obtain a second reaction solution. (0164) (c) The second reaction solution was filtered to collect the solid precipitate from the second reaction solution. Then the solid precipitate was washed with 40 wt % methanol solution and dried to give white powdery diacetal clarifying agent of 1,3:2,4-di(3,4-dimethyl-benzylidene)-D-sorbitol (6613 grams, yield 80.8% calculated from 8185 grams of theoretical mass). Based on the total weight of the produced powdery diacetal clarifying agent, the amount of the Ultramarine Blue was about 0.02 wt %. The produced powdery diacetal clarifying agent of Example 2 had the following characteristics: (0165) i. Melting point: 274.45° C. and crystallization temperature: 227.99° C. (0166) ii. Data of 1H-NMR spectrum (400 MHz, d6-DMSO): δ 7.23-7.11 (m, 6H), 5.58 (s, 2H), 4.81 (d, 1H), 4.41 (t, 1H), 4.14-4.09 (m, 3H), 3.88 (s, 1H), 3.81-3.74 (m, 2H), 3.65-3.57 (m, 1H), 3.50-3.40 (m, 1H), 2.24 (s, 12H). (0167) iii. Data of FTIR spectrum: λ3212, 2939, 2858, 1505, 1453, 1400, 1372, 1340, 1262, 1245, 1213, 1168, 1125, 1098, 1068, 1026, 998, 898, 881, 857, 824, 790, 769, 714, 668, 632, 578, 543, 475, 436 cm-1. (0168) iv. Data of UV/VIS spectrum: absorbance at 265 nm: 1.5606; absorbance at 649 nm: 0.0007. (0169) v. Ash content: 0.01%. (0170) vi. Purity determined by LC: 99.75%. (0171) vii. GC analysis result of the residue of aromatic aldehyde: no 3,4-dimethyl benzaldehyde was detected. |
| 80% |
With methanesulfonic acid; choline chloride In methanol at 26℃; for 8h; |
13
Example- 13; The choline chloride (1.4 gm) and methanesulfonicacid (MSA) (0.96 gms) were added to methanol (30 ml) and mixed well to prepare the ionic fluid. 3,4 dimethyl benzaldehyde (1.5 ml) and sorbitol (1.5 gm) were added to the ionic fluid and stirred to initiate the reaction at 26°C. The thick solid mass formed after few minutes of starting the reaction and the reaction was continued for 8 hrs. The solid product was filtered and washed with 100 ml diethylether. The white solid product was dried in oven at 95°C for 2 hrs followed by air dried for 4 hrs for measuring the yield. The yield and purity were found to be 80% and 99.8% respectively. |
| 80% |
With methanesulfonic acid; choline chloride In methanol at 26℃; for 8h; |
13 EXAMPLE 13
General procedure: EXAMPLE 13 [0095] The choline chloride (1.4 gm) and methanesulfonicacid (MSA) (0.96 gms) were added to methanol (30 ml) and mixed well to prepare the ionic fluid. 3,4 dimethyl benzaldehyde (1.5 ml) and sorbitol (1.5 gm) were added to the ionic fluid and stirred to initiate the reaction at 26° C. The thick solid mass formed after few minutes of starting the reaction and the reaction was continued for 8 hrs. The solid product was filtered and washed with 100 ml diethylether. The white solid product was dried in oven at 95° C. for 2 hrs followed by air dried for 4 hrs for measuring the yield. The yield and purity were found to be 80% and 99.8% respectively. |
| 77% |
In methanol at 26℃; for 5h; |
1
Example: 1; Toluene-4-sulphonic acid monohydrate (PTSA), a hydrogen donor (2gms) was mixed with sodium chloride (0.6 gms) in equal mole ratio and 30 ml methanol was added to the salt mixture and stirred well to prepare ionic fluid. The ionic fluid obtained was used for carrying out the dehydration reaction at 26°C. 3,4 dimethyl benzaldehyde and sorbitol in 2: 1 mole ratio were added to the ionic compound and stirred to initiate the reaction. The solid mass formed within few minutes of starting the reaction. The stirring speed was increased to keep the mass in suspension condition and reaction was continued for 5 hrs. The solid product was filtered to obtain mother liquor and a white solid mass. The white solid mass was washed with 120 ml methanol. The white solid product was dried in oven at 95°C for 2 hrs followed by air dried for 4 hrs for measuring the yield. The yield was found to be 77%. |
| 63% |
In methanol; water |
10 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 10 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol The target molecule was synthesised using similar procedure as described in Example 5 with D-sorbitol (9.11 g, 50 mmol), 3,4-dimethylbenzaldehyde (13.4 g, 100 mmol), and concentrated hydrochloric acid (0.5 mL g, 6 mmol) in methanol (100 mL). After the same purification procedure as described in Example 5, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (13.0 g, 63%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
| 55% |
In nitromethane |
3 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 3 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol The target molecule was synthesised using similar procedure as described in Example 1 with D-sorbitol (9.11 g, 50 mmol), 3,4-dimethylbenzaldehyde (13.4 g, 100 mmol), and p-toluensulfonic acid monohydrate (1.9 g, 10 mmol) in nitromethane (100 mL). After the same purification procedure as described in Example 1, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (11.4 g, 55%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
| 55% |
In 1,4-dioxane |
2 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 2 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol The target molecule was synthesised using similar procedure as described in Example 1 with D-sorbitol (9.11 g, 50 mmol), 3,4-dimethylbenzaldehyde (13.4 g, 100 mmol), and p-toluensulfonic acid monohydrate (1.9 g, 10 mmol) in 1,4-dioxane (100 mL). After the same purification procedure as described in Example 1, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (11.4 g, 55%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
| 50% |
In methanol at 20℃; for 12h; |
5 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 5 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol To the white slurry of D-sorbitol (9.11 g, 50 mmol) and 3,4-dimethylbenzaldehyde (13.4 g, 100 mmol) in methanol (100 mL) at room temperature was added a solid of tin dichloride dihydrate (2.3 g, 10 mmol). After magnetically stirring for 12 h, the gel-like material (no visible solvent present) was washed sequentially with boiling water (200 mL*2), cyclohexane (200 mL*2) and boiling water (200 mL*4). After drying in vacuum oven at 110° C. for 12 h, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (10.3 g, 50%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
| 8% |
In N,N-dimethyl-formamide |
4 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol
EXAMPLE 4 1,3:2,4-Bis(3',4'-dimethylbenzylidene) Sorbitol The target molecule was synthesised using similar procedure as described in Example 1 with D-sorbitol (9.11 g, 50 mmol), 3,4-dimethylbenzaldehyde (13.4 g, 100 mmol), and p-toluensulfonic acid monohydrate (1.9 g, 10 mmol) in N,N-dimethylformamide (DMF, 100 ml). After the same purification procedure as described in Example 1, 1,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol (1.7 g, 8%) was obtained as a white powder. The product was properly characterized using 1H and 13C NMR, IR and GC/MS. |
|
With toluene-4-sulfonic acid In methanol; cyclohexane at 65℃; for 6.5h; Dean-Stark; Reflux; |
4
A 500 ml four necked round bottom flask equipped with a Dean-stark trap, condenser, thermometer, and a mechanical stirrer was charged with 130 ml of cyclohexane, 0.5 gms of para toluenesulfonic acid as a catalyst and 15.5 ml of 3, 4-dimethylbenzaldehyde . To the well stirred hot reaction mixture (65° C.), a solution of 10 gms of sorbitol dissolved in 60 ml methanol was added over a period of 30 minutes. The reaction is stirred and heated under reflux for six hours. The reaction mixture is stirred at 350 rpm and the torque monitored constantly. The azeotrope was removed continuously and reaction vessel is replenished with fresh solvent. After six hours, reaction mixture was cooled, neutralized with sodium hydroxide. The product was filtered under vacuum to remove mother liquor containing methanol, cyclohexane, unreacted 3,4-dimethyl benzaldehyde, mono intermediate of DMBDS. The product was washed with hot water (65° C.) (2×200 ml) and filtered. The product is finally washed with methanol (500 ml), filtered and dried over night in a vacuum oven at 100° C. DMDBS was obtained with purity of 99.5% and 90%-95% yield. |
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