Toluene distillation

Food Dissolve (toluene) distil under GC/EC 0.35 mg/kg US Food and Drug... 

Analysis of Spray Dried Samples. Moisture content was determined in duplicate via toluene distillation and total volatile oil by Clevenger (l ). Surface oil was measured by Soxhlet extraction (2). Shelf-life was determined by gas chromatography (6) the end of shelf-life was the time taken (at 37 C storage) to reach a limonene epoxide concentration of 2 mg/g oil. 

Moisture. Moisture was determined by the toluene distillation method. A 40 g sample of powder was added to 250 mL toluene in a 500 mL flask. The flask was fitted with a Bidwell-Sterling trap and the sample brought to a boil on a hot plate. The distillation was carried out for 2i hr. The distillate was allowed to cool to room temperature before the volume of water was read directly from the trap. 

The resultant powders were analyzed for moisture content (toluene distillation), surface oil (Soxhlet... 

Moisture Determination. Sample moisture was determined by using a modified A.O.A.C. toluene distillation method (7) for both the powders stored at 37 C (a adjusted over Mg(NO3)2T and the powders stored at 4 C (a unadjusted). Toluene (175mL) was added to 40g of unadjusted powder or 20g of adjusted powder in a 500 mL flat bottomed flask fitted with a Bidwell-Sterling trap and water cooled condenser. Samples distilled for 3 hours and then the volume of water collected was recorded. 

Moisture Determination. There are many methods available for moisture determination. The commonly used toluene distillation method is still regarded as adequate and accurate for quality control situations by Anandaraman and Reineccius (TO). This method was employed in this study. A 10.0 gm sample was used and the distillation was continued for 4-5 hours. 

Moisture. The moisture contents as determined by toluene distillation ranged from 2.1-5.5% w/w. The lowest value was obtained for the SD M250 sample while the highest value was seen with the beta-cyclodextrin complex. 

The water of crystallization can be moved from a-hydrate by refluxing it in a high-boiling organic solvent that is immiscible with water. For example, the moisture in lactose hydrate has been determined by the toluene distillation method that is often used to determine moisture in milk powder with lactose, prolonged distillation (5 hr) is necessary to remove the hydrate moisture. The powder remaining after distillation in a stable anhydrous form (Nickerson 1974). 

Benzene and toluene by-products are recovered in the overhead of the benzene-toluene distillation column. The bottoms from the benzene-toluene column are distilled in the ethylbenzene recycle column, where the separation of ethylbenzene and styrene is effected. The bottoms, are pumped to file styrene finishing column. The overhead product from this column is purified styrene. The bottoms are further processed in a residue-finishing system to recover additional styrene from the residue. 

The toluene layer is transferred to a i-l. flask, without drying, and the unchanged toluene distilled off the ditolylethane is then collected over a range of 295-3 io°. There is practically no intermediate fraction, but a tarry residue of about 75 g. remains in the flask. Upon redistillation, the ditolylethane is... 

S. Cuprous iodide-triethyl phosphite complex (2). (Note 5). A 1-L, round-bottomed flask equipped with a magnetic stirrer and reflux condenser is flame-dried under nitrogen. The vessel 1s charged with 38.2 g (0.20 mol) of cuprous iodide, 33.4 mL (0.20 mol) of triethyl phosphite (Note 6) and 400 mL of dry toluene (distilled from CaH ). The mixture is stirred at 80°C for 8 hr, cooled to room temperature, and filtered under reduced pressure on a pad of Celite. The solvent is removed from the filtrate successively with a rotary evaporator and briefly (15 min) under high vacuum. The residual solid is recrystallized from ether (25 mL) to yield 41.1-49.9 g (57.4-69.8J) of cuprous iodide-triethyl phosphite complex in two crops, mp 114-115°C. 

The crude ester obtained in this way was then treated with a solution of 7.5 g of flaked sodium hydroxide in 67.5 ml of water. The mixture was introduced into a 250 ml spherical flask, equipped with a condenser, and then the reaction medium was slowly brought to 60°-70°C. This temperature was maintained for 3 hours, whereafter the mixture was cooled to about 50°C and the ethanol which had formed and the residue of n-propanol were eliminated under a pressure of 70 mm Hg. The solution thus obtained was cooled to 20°C and acidified, while stirring, by addition of 26.25 g of 36% hydrochloric acid. During this operation, the temperature of the reaction medium was kept below 40°C by cooling. Stirring was continued for 30 minutes, whereafter the mixture was left standing for 30 minutes. The oily layer of di-n-propyl cyanacetic acid was decanted and the aqueous phase extracted with 35 ml of toluene. The extract in toluene was then added to the decanted di-n-propyl cyanacetic acid, whereafter the solution in toluene was washed, in a separation funnel, with a solution of 1.5 g of sodium chloride in 14 ml of water. The toluenic phase was decanted and the toluene distilled under atmospheric pressure. 

Much effort has been devoted to the optimization of the polyesterification reaction. For instance, different types of monomeric precursors structurally related to succinic acid (e.g., dimethyl succinate or succinic anhydride) were used. Different kinds of catalysts (e.g., phenolates, titanium alkoxides, tin octanoates) at different concentrations were studied. Different reaction temperatures (130-190 °C) were reached and different procedures for water elimination (vacuum drying under different conditions or toluene distillation) were adopted. Experimental results obtained showed that the use of different catalysts and different monomer precursors (succinic acid derivatives) did not significantly alter the polymerization kinetics or yield, and for this reason, they were abandoned. The procedure finally adopted is summarized below. 

After toluene distillation, the contents of tank 25 are sampled for toluene content, which should not exceed 1.5%. When the analysis is satisfactory, the technical product is cooled to 60 °C with water sent into the tank jacket, loaded into collector 29 by compressed nitrogen flow (0.07 MPa) and pumped into apparatus 31 for purification. The purification is done with active coal or askanite. Apparatus 31 is loaded with 1-2% of coal or 4-6% of askanite (as against the quantity of the loaded product of hydrolytic condensation). After loading the adsorbent, the contents of the apparatus are heated to 120-140 °C and agitated at this temperature for 3-4 hours. 

Whether the toluene distillation and product polycondensation is finished, is determined by viscosity or gelatinisation time, and by solid residue. The jacket of apparatus 15 is filled with water to cool the varnish to 40 °C the cooled varnish self-flows into settling boxes 20. After settling, the varnish is sent to ultracentrifuge 21, and the waste accumulated in the bottom part of the settling boxes is periodically loaded off into containers and used to paint factory equipment. 

The polymerisation is carried out in a reactor with an agitator and a water vapour jacket in the presence of a catalyst (10-12% alcohol solution of potassium hydroxide) at 20+5 °C. The polymerisation is continued until the product attains a certain viscosity after that, the reactor is loaded with a required amount of dimethyldichlorosilane to break the chain, with an addition of toluene to dilute the varnish. The polymer is treated with dimethyldichlorosilane for 3-5 hours at agitation the end of the stage is monitored by the universal indicator. The varnish is filtered to eliminate mechanical impurities and potassium chloride and sent to repeated toluene distillation, which is continued until the varnish attains the necessary viscosity and polymer content. 

Thus, Graetz331 reacted functional PEO prepolymer first with a cyclic anhydride and subsequently with glycidyl methacrylate. Efficient removal of the water in the monohydroxy PEO is however required before starting the synthesis. This is achieved by azeotropic toluene distillation ... 

The product from Step 4 (27.8 mol) was dissolved in 3-pentanone (279 mol) containing 70% perchloric acid (0.39 mol), stirred for 18 hours, the volatiles removed, and fresh 3-pentanone (348 mol) added. The reaction mixture was filtered, toluene (18 kg) added, and the solution washed successively with 6% aqueous NaHC03 (19 kg), water (18 kg), and brine (24 kg). The mixture was distilled and toluene (24 kg) gradually added until no additional toluene distilled over and the ketal isolated in 100% yield. 

By toluene distillation for 2 hr or less. As a 5% solution in colorless mineral oil. By specified cone penetrometer test. 

Moisture. The water content of lecithin products is usually less than 1.0%. As a consequence of lecithin s essentially moisture-free state, lecithin products have very low water activity and do not adversely contribute to the microbiological profile of most food systems. Most lecithin products are preserved well in storage. Higher moisture levels usually indicate a greater potential for spoilage or chemical degradation. Moisture is determined by AOCS Official Method Ja 2b-87 (77). A less accurate moisture level can also be determined by azeotropic toluene distillation (AOCS Official Method Ja 2-46) (77). One cannot determine lecithin moisture by vacuum oven methods. These methods are known to degrade lecithin products and yield false moisture levels. 

To the polymer [NPCl2]2—[NP(CH3)(CH2SiMe3)] and the residual cyclic trimer, ge/n-N3P3Cl4(CH3)(CH2SiMe3), in an airless flask is added 300 mL of dry toluene (distilled over sodium benzophenone). This mixture is stirred under an atmosphere of dry nitrogen until the contents of the broken tube dissolve (3-4 hr). The toluene solution is then transferred to a 500-mL addition funnel under a nitrogen atmosphere via a double-tipped syringe needle. 

After the soxhlet extraction and drying of the extract are completed, the extract is dissolved in pentane first. An ultrasound bath can be used to improve solving. This solution of extract in pentane is filtered. After filtration, the extract is separated into two fractions pentane soluble fraction or filtrate and the remainder. The pentane soluble fraction is composed of compounds that have similar polarity as pentane or the liquid at the filtration temperature. The remainder contains the asphaltene fraction and precoke. This remainder is dissolved in toluene in the same manner as the extract was solved in pentane, and then filtered. The asphaltene fraction is the filtrate after filtration with toluene, and precoke is the remainder. The solvents (pentane and toluene) are removed from the filtrates by distillation at 40°C and normal pressure for pentane distillation, and 70 mbar for toluene distillation. 

Assuming that you had 100% efficiency, how much toluene distilled in order to drive off the H O Use equation... 

---