Chemical News

Tuesday, April 21, 2009

Ethylene Glycol without Ethylene Route

A route for making ethylene glycol without starting from ethylene is under development. Shell Chemical is a leading provider of ethylene glycol (EG) process technology. The conventional process for making EG is hydrolysis of ethylene oxide (EO), which is made by oxidizing ethylene over a silver catalyst.

For many years, the selectivity of the ethylene oxidation has been no better than ~85%; however, lately Shell has developed catalysts that are capable of achieving 90% selectivity. EO hydrolysis is typically carried out noncatalytically in a large excess of water. The selectivity to EG is only ~90%; diethylene glycol, and triethylene glycol are the byproducts. As one remedy, Shell now offers a two-step process for converting EO to EG via an ethylene carbonate intermediate that produces EG in almost 100% selectivity.

A. Lenero and colleagues at Shell are working on a different route to EG—one that does not begin with ethylene. Their method proceeds by hydroformylating formaldehyde to give glycolaldehyde, which can undergo hydrogenolysis to make EG. The first step is the difficult part, and the key to this invention is an improved catalyst for the hydroformylation step.

In one example, 0.15 mol of formaldehyde (in the form of 37% aqueous formalin), 37 mL (0.22 mol) of N,N-dibutylacetamide, 7.5 mL of water, 0.49 mmol of Rh(acac)(CO)2, 0.96 mmol of 2-phospha-2-(ethyl-N,N-dimethylamido)-1,3,5,7-tetramethyl-6,9,10-trioxa-tricyclo[3.3.1.1{3,7}]-decane, and 9.1 mmol of trimethylbenzoic acid are added to an autoclave. After the air is flushed out, the autoclave is pressurized to 3 MPa with CO and heated to 90 °C for 5 h. The conversion of formaldehyde is 90%, and the yield of glycolaldehyde is calculated to be 90%. In a separate example, glycolaldehyde is easily converted to EG by hydrogenolysis at 40 °C over Raney nickel. (Shell Oil [Houston]. US Patent 7,511,178




Source: CAS Patent Watch

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Tuesday, March 10, 2009

Flavoring Compound Synthesis by Enzymatic Esterification

cis-Pellitorin (1) is isolated from the tarragon plant. It used as a pungent flavoring to give a “hot” taste to foods and oral hygiene products. I.-L. Gatfield and co-inventors describe a method of preparing synthetic 1 by the reaction of ester 2 and i-BuNH2 in the presence of an enzyme catalyst.



The crude product is purified by silica gel chromatography and isolated in ~80% yield with a GC purity of 99.4%. The patent claims do not mention a specific enzyme catalyst, but specify that it must have lipase activity and is on a support. The enzyme used in the examples is Chirazyme L-2 from Roche.

The examples indicate that the reaction can be carried out without solvent or in toluene. The concentration of the enzyme is ~40 wt% of the amount of ester 2. Much of the discussion in the patent relates to plants or molecules with similar pungent taste properties. There are also details on the preparation and the testing of flavors for chewing gum, mouthwash, and toothpaste using 1. 1H and 13C NMR data for 1 are given. The patent does not provide a preferred method for isolating and purifying 1 on a commercial scale, although one example mentions molecular distillation

Source: CAS & Patent Watch

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Thursday, February 5, 2009

Variable Compression Engine


Lotus Engineering has been hard at work developing new engine technologies that allow the use of sustainable alcohol fuels. It's recent Exige 270E Tri-Fuel concept showed that the British firm knows how to make an engine run on various fuels, including gasoline, ethanol and methanol. In fact, the 270E Tri-Fuel concept was the most powerful Exige ever conceived by the Hethel-based company and made its highest power output using synthetic methanol fuel. Lotus has started a new research project called the OMNIVORE engine -- cleverly indicating that it will run on anything -- that uses a single cylinder with direct injection and a variable compression ratio in order to maximize power and efficiency while running on various alcohol fuels. The higher octane rating of alcohol fuels will allow the engine to run with higher compression, thereby offering more power, while also toning itself down to run on lower-grade fuels as well. Read Full article here.

Source - AutoBlog.com

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Saturday, January 31, 2009

Small Scale BioGas

Cornell plant scientists have invented a new method that uses manure and other farm byproducts to remove toxic hydrogen sulfide from biogas -- a renewable energy source derived from the breakdown of animal waste.

Hydrogen sulfide can combine with water to cause acid rain and to corrode engines. Its removal makes biogas a more viable alternative fuel source. The new method will be marketed under the name SulfaMaster.

"SulfaMaster has a very large potential application for distributed bioenergy production at small sites around the country," said Gary Harman, professor of plant biology at the New York State Agricultural Experiment Station in Geneva.

Harman and Terry Spittler, a retired analytical chemist at Cornell, own Terrenew, a small company at Cornell Agriculture and Food Technology Park in Geneva that will market the product. In addition, Terrenew markets two other products that also use agricultural waste to help clean up environmental contaminants, including oil spills and heavy metals, from water.

With more than 9 million dairy cows in the United States, each producing on average more than 120 pounds of manure daily, biogas is already a key energy source for many sustainable farms. It's created by anaerobic digestion -- a process by which microorganisms break down manure and other organic matter in the absence of oxygen. The resulting biogas contains high levels of methane and carbon dioxide, but also a small amount of hydrogen sulfide.

Most methods for hydrogen sulfide removal require expensive industrial scrubbers that are not feasible for smaller farms.

"In most cases, these methods are meant for oil refineries and are not suited to small-scale use," Harman said.

On the other hand, Terrenew's process uses manure as a major component of a special medium, which is placed in barrels. "The gas is then piped into the bottom of barrels, [and as it] passes through the medium, the hydrogen sulfide is removed," Harman explained. "The resulting clean methane (plus carbon dioxide) can then be used for energy."

Harman estimates that the SulfaMaster medium can be reused up to six times before it needs to be replenished in the biogas mixture.

The new product also has promise off the farm. Biogas is prevalent in sewage treatment plants and landfills, especially those that accept construction and demolition waste. These sites can capture cleaner biogas and use it to power their operations.

Terrenew, using partial funding from the New York State Energy Research and Development Authority, demonstrated the product last summer at El-Vi Farms in Phelps, N.Y., and found promising results. The company plans to run another test to remove hydrogen sulfide from a landfill before releasing SulfaMaster. Last month, the Cornell Center for Technology Enterprise and Commercialization filed a patent on the technology that will be licensed to Terrenew

However, I have a better option to remove Sulfur from biogas.

Source: Cornell University

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Tuesday, January 20, 2009

New Process for Propylene Oxide Manufacturing


Propylene oxide (PO) production technology is undergoing something of a renaissance. After 1974, when the first propylene oxide–styrene monomer technology plant came on stream, no new PO technology was put into use until 2003, when Sumitomo Chemical started up its new coproduct-free route to PO that was based on cumene hydroperoxide as the propylene epoxidizing agent.

This innovation spurred others to develop alternative ways to make PO, such as direct-oxidation and H2O2-based routes. Another method is the so-called hydro-oxidation route, in which propylene is exposed to a mixture of oxygen and hydrogen. This route has been plagued by low productivity because of very low conversions per pass.

H. Abekawa, T. Kawabata, and M. Yako disclose a technique in which the productivity of propylene hydro-oxidation is increased and selectivity to PO is maintained at relatively high levels. The key to the inventors’ method is adding polycyclic compounds such as anthracene, naphthalene, tetracene, and pyrene to the reaction solvent in the presence of titanium silicalite and supported palladium catalysts. For example, a propylene oxide reaction was carried out in an autoclave at 60 °C and 0.8 MPa pressure by feeding a 4:4:10:82 propylene–oxygen–hydrogen–nitrogen gas mixture at 20 L/h and a H2O–MeCN 20:80 w/w solution containing 0.7 mmol/kg of anthracene and 0.7 mmol/kg of NaH2PO4 at 108 mL/h. Ti-silicalite (0.133 g) and Pd/C (0.33 g) activated carbon were added to the reaction mixture. PO was made in 87% selectivity based on the amount of propylene consumed; almost all of the remaining propylene was converted to propane. Productivity, defined as the amount of PO made per unit weight of titanium catalyst, was 33.5
Source: CAS Patent Watch

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