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With propylamine; hydrogen;molybdenum promoted RANEY type nickel catalyst; In methanol; at 35℃; under 36961.4 Torr;Autoclave; Industry scale;Product distribution / selectivity; |
Examples 1-82-Amino-2-Ethyl-1,3-PropanediolExamples 1-8 relate to 2-amino-2-ethyl-1,3-propanediol (AEPD), which may be prepared from 1-nitropropane and formaldehyde).The analytical (characterization) methods used in the examples are as follows.GC Analysis. An HP 5890 Series II Gas Chromatograph with a J&W DB-5 column, 30 m*0.25 mm*1.0 mum is used to monitor effects of process changes on GC area %. The FID detector is set at 250 C. and the injector at 180 C. Oven temperature program: 60 C. for 4 minutes, ramp at 30 C./min to 220 C., hold 7 minutes, ramp at 20 C./min to 280 C., and hold 2 minutes. The injection volume was 1 muL with split ratio of 100:1 and helium as carrier gas.HPLC Analysis. The concentration of 2-nitrobutanol (2-NB), an undesired side product of the condensation reaction, and 2-nitro-2-ethyl-1,3-propanediol (NEPD) are determined by HPLC analysis. Using Waters 2695 Separations Module, HPLC analysis is performed with Alltech OA-1000 size exclusion column. The mobile phase is 0.01 N H2SO4 solution. Detection is achieved using Waters 996 Photodiode Array Detector at wave length of 273 nm. Five standard solutions containing both 2-NB and NEPD are prepared for calibration.Titration Parameters-Percent Free Formaldehyde. The amount of free formaldehyde is determined by reaction and titration. Hydroxylammonium chloride (NH2OH.HCl) reacts with formaldehyde to form hydrochloric acid. The hydrochloric acid is titrated with sodium hydroxide from which the percent of free formaldehyde is determined. Autotitrator 726 Titroprocessor from Metrohm Ltd. is used for titration. The instrument is calibrated with pH standard solutions at 4, 7, and 10 before titration. 0.1 N NaOH is used as titrant and deionized water as solvent. A blank is analyzed in the same manner as the sample.Percent Water by Karl Fischer. Water content in the sample is determined by potentiometric detection using volumetric Karl Fischer (KF) titration. Hydranal-Composite 5 is used as titrant and methanol as solvent.Experimental procedures used in Examples 1-8 are described below.Nitroalcohol Adjustment (NEPD with varying levels of free formaldehyde). For these studies, commercial NEPD concentrate is analyzed for weight percent (wt/wt) NEPD, 2-NB, and free formaldehyde. In order to understand the effect of excess formaldehyde on the composition of the NEPD product, the following study is conducted. To 10 g samples of NEPD solution is added 0.27, 0.54, 0.81, and 1.08 g of 37% aqueous formaldehyde. The samples are placed in a 40 C. water bath for 2 hours and analyzed. Analytical results are shown in Table 1. TABLE 1 weight percent 37% aqueous free formaldehyde added NEPD 2-NB formaldehyde none 66.06 4.26 0.05 0.27 g 67.46 1.38 0.28 0.54 g 66.80 0.51 1.24 0.81 g 66.32 0.29 2.11 1.08 g 64.05 0.23 2.88 With this information, the NEPD concentrate is adjusted to a desired formaldehyde level by charging a certain amount of 37% aqueous formaldehyde, mixing, and heating to 40 C. for 2 hours.Hydrogenation (reduction of NEPD to AEPD). The reactor used for these experiments is a two liter Parr 316 stainless steel autoclave equipped with a Parr model 4842 controller. The system is furnished with internal cooling coils and an external heating mantle for temperature control. The reactor is fitted with a magnetically driven agitator shaft with 3 pitched blade turbine impellers.The autoclave is charged with 240 g methanol, RANEY 3111 (a molybdenum promoted RANEY type nickel catalyst) at 5% loading based on the nitroalcohol feed, and 1-propylamine at 0-28 mole % based on nitroalcohol feed and free formaldehyde level. The autoclave is sealed, pressure purged 3 times with nitrogen (N2), 3 times with hydrogen (H2), and then pressured to and regulated at approximately 700 psig H2. Agitation is begun and set at 600 rpm. Heating is applied until the autoclave temperature reaches 35 C. The cooling water solenoid is set to control the reaction temperature at 55 C.The nitroalcohol feed is pumped to the reactor using an Eldex Duros model CC-100-S high pressure positive displacement pump. The supply side of the pump is connected to a graduated cylinder and the delivery side is fitted with a relief device. Depending on the amount of free formaldehyde in the NEPD solution (0.05-5.0%), 900-1000 g NEPD solution is pumped to the autoclave. The autoclave contents are sampled for GC analysis at 25, 50, and 75% of the NEPD feed. Following completion of the feed, the contents are held for 10 minutes at constant temperature under hydrogen pressure. The autoclave is then cooled to 25 C., vented, and purged with N2. The reaction product (final sample) is filtered through a glass microfiber filter to remove catalyst, transferred to glass bottles, and analyzed by GC.Concentration. A Buechi rotary evaporator, model 011, is used in the laboratory to remove methanol, propylamines, and enough water to produce 2-amino-2-ethyl-1,3-propanediol (AEPD) at 85 concentration. The pressure in the... |
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