1,3-Propanediol from ethylene oxide

Powell JB, Slaugh LH, Mullin SB, Thomason TB, Weider PR. (1999) Cobalt catalyzed process for preparing 1,3-propanediol from ethylene oxide. Shell Oil Company. U.S. Patent 5981808. 

In the first process the yield does not exceed 65% of the starting compound due to simultaneous formation of 1,2-propanediol, while, in the second, a yield of 80% is obtained. Adding the fact that the market price of ethylene oxide is lower than acrolein, the Shell process can be regarded as economically more favorable. This is reflected in the much higher production volume reported for the production of 1,3-PD from ethylene oxide, which amounted to 45,000 t/a in 1999 as opposed to 9000 t/a from acrolein. The relatively high production costs with the acrolein process have probably induced the Dupont Company to invest in research efforts to further develop the biological process (see below). 

The superior properties of polypropylene terephthalate) (PPT) polymer and fibers over the chemically analogous poly(ethylene terephthalate) (PET, used for soda bottles) and poly(butylene terephthalate) (PBT) have been well known for several decades PPT fibers are much more elastic and less brittle than PET and offer better recovery from stretching than PBT they are also easier to dye than either PET or PBT. Compared to the intermediate for PET, ethylene glycol, which is available inexpensively from ethylene oxide, and to that for PBT, butanediol, likewise available inexpensively from butene or butadiene, the intermediate for PPT, 1,3 propanediol (1,3-PPD or PDO), was not - and on a large scale is still not - available. Three processes, two chemical ones and one biotechnological, compete to change this situation (Figure 20.10). 

Propanediol (1,3PD) is also undergoing a transition from a small-volume specialty chemical into a commodity. The driving force is its application in poly (trimethylene terephthalate) (PTT), which is expected to partially replace polyethylene terephthalate) and polyamide because of its better performance, such as stretch recovery. The projected market volume of PTT under the trade-names CORTERRA (Shell) and Sorona 3GT (Dupont) is 1 Mt a-1 within a few years. In consequence, the production volume of 1,3PD is expected to expand from 55kta-1 in 1999 to 360 kt a-1 in the near future. 1,3PD used to be synthesized from acrolein by Degussa and from ethylene oxide by Shell (see Fig. 8.8) but a fermentative process is now joining the competition. 

Scheme 4.2 Chemical synthesis of 1,3-propanediol by Shell method starting from ethylene oxide.

Propanediol is produced either from the reductive hydration of acrolein (Degussa-DuPont process), or through reductive carbonylation of ethylene oxide (Shell process), or through fermentation of glucose via glycerol (DuPont-Genencor process). 

Other Uses of Ethylene Oxide. About 2 percent of ethylene oxide is consumed in miscellaneous applications, such as its use as a raw material in manufacture of choline, ethylene chlorohydrin, hydroxyethyl starch, and hydrox-yethyl cellulose and its direct use as a fumigant/ sterilant. Production of 1,3-propanediol via hydroformylation of ethylene oxide was begun on a commercial scale in 1999. 1,3-Propanediol is a raw material for polytrimethylene terephthalate, which finds uses in fibers, injection molding, and in film. Use of ethylene oxide in making 1,3-propanediol is expected to be as much as 185 million lb by 2004, up from 12 million lb in 1999. 

Chemical routes to polypropylene terephthalate-based fibers, which we have branded Sorona, use hazardous chemicals such as ethylene oxide and carbon monoxide and are subject to the environmental problems of a typical chemical process (Figure 7). We undertook the enormous challenge of producing 1,3-propanediol (3G) from glucose in one step as shown in Figure 8. 

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. 

Ethers and esters of various glycols-See Cunne Johnston, PP 305, 306, 309, 311, 313, 322 2-Ethyl 2-buryl-l, 3-propanediol 3 0 Ethylene chlorhydrin 0.095 (3.5g inhaled from the atmosphere killed a man) Propylene glycol 26.4 Propylene oxide 1.14 Propylene oxide tetratner 1.8 Tri ethyleneglycol 22.1 Trim ethylenegly col (about twice as toxic to small animals as propylenegly col) ... 

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