1.3- Propanediol production

Yasuda S, Mukoyama M, Horikawa H, Toraya T, Morita H. (2007). Process for producting 1,3-propanediol and or 3-hydroxypropionic acid. US Patent 20070148749. 

The main intermediates in the pentaerythritol production reaction have been identified and synthesized (50,51) and the intermediate reaction mechanisms deduced. Without adequate reaction control, by-product formation can easily occur (52,53). Generally mild reaction conditions are favored for optimum results (1,54). However, formation of by-products caimot be entirely eliminated, particularly dipentaerytbritol and the linear formal of pentaerythritol, 2,2 -[meth5lenebis(oxymethylene)]bis(2-hydroxymethyl-1,3-propanediol) [6228-26-8] ... 

HVP products prepared by hydrolysis with HCl contain varying amounts of glycerol chlorohydrins, such as 3-chloro-l,2-propanediol [96-24-2] and l,3-dichloro-2-propanol [96-23-1J, depending on reaction conditions and Hpid contents of the starting material (135). As a result of their toxicides, regulating agencies in many countnes have restncted the contents of these compounds in food. 

Preparation. The industrial production of malonic acid is much less important than that of the malonates. Malonic acid is usually produced by acid saponification of malonates (9). Further methods which have been recendy investigated are the ozonolysis of cyclopentadiene [542-92-7] (10), the air oxidation of 1,3-propanediol [504-63-2] (11), or the use of microorganisms for converting nitriles into acids (12). 

The nitro alcohols in Table 1 are manufactured in commercial quantities however, three of the five of them are used only for the production of the corresponding amino alcohols. 2-Methyl-2-nitro-l-propanol (NMP) is available as the crystalline soHd or as a mixture with siHcon dioxide. 2-Hydroxymethyl-2-nitro-1,3-propanediol is available as the soHd ( 9.15/kg), a 50% solution in water ( 2.33/kg), a 25% solution in water ( 1.41/kg), or as... 

Polymers. AH nitro alcohols are sources of formaldehyde for cross-linking in polymers of urea, melamine, phenols, resorcinol, etc (see Amino RESINS AND PLASTICS). Nitrodiols and 2-hydroxymethyl-2-nitro-l,3-propanediol can be used as polyols to form polyester or polyurethane products (see Polyesters Urethane polymers). 2-Methyl-2-nitro-l-propanol is used in tires to promote the adhesion of mbber to tire cord (qv). Nitro alcohols are used as hardening agents in photographic processes, and 2-hydroxymethyl-2-nitro-l,3-propanediol is a cross-linking agent for starch adhesives, polyamides, urea resins, or wool, and in tanning operations (17—25). Wrinkle-resistant fabric with reduced free formaldehyde content is obtained by treatment with... 

Nitromethane. The nitroparaffins are used widely as raw materials for synthesis. Nitromethane is used to produce the nitro alcohol (qv) 2-(hydroxymethyl)-2-nitro-l,3-propanediol, which is a registered biocide useful for control of bacteria in a number of industrial processes. This nitro alcohol also serves as the raw material for the production of the alkanolamine (qv) 2-amino-2-(hydroxymethyl)-l,3-propanediol, which is an important buffering agent useful in a number of pharmaceutical appHcations. 

Meth5l-l,3-propanediol is produced as a by-product. The hydroformylation reaction employs a rhodium catalyst having a large excess of TPP (1) and an equimolar (to rhodium) amount of 1,4-diphenylphosphinobutane (DPPB) (4). Aqueous extraction/decantation is also used in this reaction as an alternative means of product/catalyst separation. 

The steric bulk of the three iodine atoms in the 2,4,6-triiodoben2ene system and the amide nature of the 1,3,5-substituents yield rotational isomers of the 5-A/-acyl-substituted 2,4,6-triiodoisophthalamides. Rotational motion in the bonds connecting the side chains and the aromatic ring is restricted. These compounds also exhibit stereoisomerism when chiral carbon atoms are present on side chains. (R,5)-3-Amino-l,2-propanediol is incorporated in the synthesis of iohexol (11) and ioversol (12) and an (3)-2-hydroxypropanoyl group is used in the synthesis of iopamidol (10). Consequendy, the resulting products contain a mixture of stereoisomers, ie, meso-isomers, or an optical isomer. 

If a similar process occurred involving the two protons at C-1, a stereochemically different situation will result. Substitution at C-1 produces a chiral product, -deuterio-, i-propanediol ... 

The two protons at C-1 are topologically nonequivalent, since substitution of one produces a product tiiat is stereochemically distinct fiom that produced by substitution of the other. Ligands of this type are termed heterotopic, and, because the products of substitution are enantiomers, the more precise term enantiotopic also applies. If a chiral assembly is generated when a particular ligand is replaced by a new ligand, the original assembly is prochiral. Both C-1 and C-3 of 1,3-propanediol are prochiral centers. 

The pinacol rearrangement is frequently observed when geminal diols react with acid. The stmcture of the products from unsymmetrical diols can be predicted on the basis of ease of carbocation formation. For example, l,l-diphenyl-2-metltyl-l,2-propanediol rearranges to... 

A solution of 32 g (030 mol) phosgene in 200 ml benzene is added dropwise at 30°C to a stirred soiution of 53.5 g (032 mol) 3-o-toloxy-13-Pfopanediol in 400 ml benzene. The mixture is stirred for an hour after the addition is completed, and a solution of 39 g of dl-methylaniline in 100 ml benzene is then added, and stirring continued for a half-hour. Ice water (about one-third volume) is then added, and the benzene layer formed is separated and stirred with 500 ml concentrated ammonia at 5°Cfor six hours. The precipitated solid (weighing about 55 g) is recovered and recrystallized from water. The product thus obtained in a yield of about 53 g is 3-(o-toloxy)-2-hydroxypropyl carbamate it is a crystalline solid melting at about 93°C, and having a lower water-solubility and higher oil-solubility than 3-o-toloxy-13-propanediol. 

A mixture of 50 parts by weight of racemic 2-acetylamino-1 -(4-methylmercaptophenyl)-1,3-propanediol, 100 parts by weight of concentrated hydrochloric acid, and 500 parts by weight of water was warmed on a steam bath for thirty minutes. The resulting solution was cooled to about 40 C and was then made strongly alkaline by addition of 35% aqueous sodium hydroxide solution. The alkaline solution was then refrigerated. The white solid which separated from the cooled solution was collected on a filter. There was thus obtained 27 parts by weight of 2-amino-1-(4-methylmercaptophenyl)-1,3-propanediol. This product melted at 130.7°C to 131 after recrystallization from methanol. 

A mixture of 1.1 g of 2-amino-1-(4-methylmercaptophenyl)-1,3-propanediol, obtained as described above and 1.6 ml of ethyl dichloroacetate was heated on a steam bath for three hours. The resulting viscous yellow oil was dissolved in 25 ml of ethylene chloride and filtered hot with charcoal, and the filtrate was allowed to cool to about 25°C. From the filtrate there separated 0,92 g of tiny white leaflets which were collected on a filter. Recrystallization of this product, which was a dextro-rotary form of 2-dichloroacetylamino-1-(4-methylmercapto-phenyl)-1,3-propanediol from nitroethane yielded the pure product, which melted at 111.6°C to 112.6°C,... 

Propanediol is a colorless liquid that boils at 210-211°C. It is soluble in water, alcohol, and ether. It is an intermediate for polyester production. It could be produced via the hydroformylation of ethylene oxide which yields 3-hydroxypropionaldehyde. Flydrogenation of the product produces 1,3-propanediol. 

Notes 1) Nitration with mixed nitric-sulfuric acid gives a less satisfactory product and a lower yield (about 52%). 2) Attempts to prepare the product starting with 2-nitro-2-(m-nitrophenyl)-propanediol-1,3 or its dinitrate were unsuccessful Its expl props were detd by R. McGill et al at the NDRC Res Lab at Bruceton, Pa and were found to be as follows ... 

Nearly insoi in w, easily sol in ale, eth, et ac, benz gelatinizes NC. Can be prepd by the nitration of ], 3-propanediol with mixed nitric-sulfuric acid, as described by Naoum (Ref 4) and Blechta (Ref 3). The nitration requires a lower temp than that used for nitrating glycerin, because the central methylene group is readily oxidized at a higher temp. A temp between 0-10° is recommended since decompn is possible even at 15°, while at 20° yel fumes are evolved. Separating the product from the spent acid occurs with ease at 10°. From lOOp of... 

Propanediol dinitrate Commercial. Barab (Ref 4) patented liq expls contg varying amts of 1,2- and 1,3-Propanediol Dinitrates. These mixts were claimed to be as powerful as, but less sensitive than NG. The product was examined by the US BuMines and found to make up a 40% straight Dynamite that compared favorably with 40% straight NG Dynamite Ref J. Barab, USP 1371215 (1921)... 

Ultralow-monol polyols, 223 Ultrapek, 327, 328 Ultraviolet (UV) radiation, 209 Ultraviolet spectroscopy, 490 Unimolecular micelle, 58 United States, phenolic production in, 375 Unsaturated maleate/O-phthalate/ 1,2-propanediol polyester prepolymer, 101-102 Unsaturated polyester resins (UPRs), 19, 29-30, 58-59... 

Alcohol oxidoreductases capable of oxidizing short chain polyols are useful biocatalysts in industrial production of chiral hydroxy esters, hydroxy adds, amino adds, and alcohols [83]. In a metagenomic study without enrichment, a total of 24 positive clones were obtained and tested for their substrate specifidty. To improve the detedion frequency, enrichment was performed using glycerol or 1,2-propanediol and further 24 positive clones were deteded in this study. 

In industrial processes, 1,3-propanediol is used for the production of polyester fibers, polyurethanes and cydic compounds [85]. 1,3-Propanediol can be produced from glucose with the limiting step catalyzed by glycerol dehydratase. A metagenomic survey for glycerol hydratases from the environment resulted in seven positive clones, one of which displayed a level of catalytic efficiency and stability making it ideal for application in the produdion of 1,3-propanediol from glucose. 

It is important that chemical engineers master an understanding of metabolic engineering, which uses genetically modified or selected organisms to manipulate the biochemical pathways in a cell to produce a new product, to eliminate unwanted reactions, or to increase the yield of a desired product. Mathematical models have the potential to enable major advances in metabolic control. An excellent example of industrial application of metabolic engineering is the DuPont process for the conversion of com sugar into 1,3-propanediol,... 

Two options are being developed at the moment. The first is to produce 1,2-propanediol (propylene glycol) from glycerol. 1,2-Propanediol has a number of industrial uses, including as a less toxic alternative to ethylene glycol in anti-freeze. Conventionally, 1,2-propanediol is made from a petrochemical feedstock, propylene oxide. The new process uses a combination of a copper-chromite catalyst and reactive distillation. The catalyst operates at a lower temperature and pressure than alternative systems 220°C compared to 260°C and 10 bar compared to 150 bar. The process also produces fewer by-products, and should be cheaper than petrochemical routes at current prices for natural glycerol. The first commercial plant is under construction and the process is being actively licensed to other companies. 

Biomass is a renewable resource from which various useful chemicals and fuels can be produced. Glycerol, obtained as a co-product of the transesterification of vegetable oils to produce biodiesel, is a potential building block to be processed in biorefineries (1,2). Attention has been recently paid to the conversion of glycerol to chemicals, such as propanediols (3, 4), acrolein (5, 6), or glyceric acid (7, 8). 

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