1,1-Dichloroethene
1,1-Dichloroethene, commonly called 1,1-dichloroethylene or 1,1-DCE, is an organochloride with the molecular formula C2H2Cl2. It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water, but soluble in organic solvents. 1,1-DCE was the precursor to the original cling-wrap for food, but this application has been phased out.
Production
1,1-DCE is produced by dehydrochlorination of 1,1,2-trichloroethane, a relatively unwanted byproduct in the production of 1,1,1-trichloroethane and 1,2-dichloroethane. The conversion involves a base-catalyzed reaction:
The gas phase reaction, without the base, would be more desirable but is less selective.
Applications
1,1-DCE is mainly used as a comonomer in the polymerization of vinyl chloride, acrylonitrile, and acrylates. It is also used in semiconductor device fabrication for growing high purity silicon dioxide (SiO2) films.
Polyvinylidene chloride
As with many other alkenes, 1,1-DCE can be polymerised to form polyvinylidene chloride. A very widely used product, cling wrap, or Saran was made from this polymer. During the 1990s research suggested that, in common with many chlorinated carbon compounds, Saran posed a possible danger to health by leaching, especially on exposure to food in microwave ovens. Since 2004, therefore cling wrap's formulation has changed to a form of polyethylene.
1,2-Dichloroethene
1,2-Dichloroethene, commonly called 1,2-dichloroethylene or 1,2-DCE, is an organochloride with the molecular formula C2H2Cl2. It is a highly flammable, colorless liquid with a sharp, harsh odor. It can exist as either of two geometric isomers, cis-1,2-dichloroethene or trans-1,2-dichloroethene, but is often used as a mixture of the two. They have modest solubility in water. These compounds have "scarcely any industrial applications," although they are fundamental given their simple stoichiometries.
Production
cis-DCE is obtainable by the controlled chlorination of acetylene:
Industrially both isomers arise as byproduct of the production of vinyl chloride, which is produced on a vast scale. Unlike vinyl chloride, the 1,2-dichloroethylene isomers do not polymerize.
These compounds are in a variety of applications including electronics cleaning, precision cleaning, and certain metal cleaning applications sold under the trade name VersaTrans.
Safety
These compounds have "moderate oral toxicity to rats."
DCE
DCE may refer to:
Terraforming
Terraforming (literally, "Earth-shaping") of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to the environment of Earth to make it habitable by Earth-like life.
The concept of terraforming developed from both science fiction and actual science. The term was coined by Jack Williamson in a science-fiction story (Collision Orbit) published during 1942 in Astounding Science Fiction, but the concept may pre-date this work.
Based on experiences with Earth, the environment of a planet can be altered deliberately; however, the feasibility of creating an unconstrained planetary environment that mimics Earth on another planet has yet to be verified. Mars is usually considered to be the most likely candidate for terraforming. Much study has been done concerning the possibility of heating the planet and altering its atmosphere, and NASA has even hosted debates on the subject. Several potential methods of altering the climate of Mars may fall within humanity's technological capabilities, but at present the economic resources required to do so are far beyond that which any government or society is willing to allocate to it. The long timescales and practicality of terraforming are the subject of debate. Other unanswered questions relate to the ethics, logistics, economics, politics, and methodology of altering the environment of an extraterrestrial world.
Terraformer (album)
Terraformer is the third album by Swiss band Knut, released in 2005 on Hydra Head Records.
Track listing
Personnel
Terraformer (comics)
Terraformer is the name of a supervillain in Marvel Comics.
Publication history
Terraformer first appeared in New Warriors #7 and was created by Fabian Nicieza, Mark Bagley, and Larry Mahlstedt.
Fictional character biography
Terraformer is a vegetable stimuloid that was created by Plantman. Terraformer gained a mind of his own. Omar Barrenos of Project: Earth recruited Terraformer to join the Force of Nature (which also consisted of Aqueduct, Firewall, and Skybreaker) to fight for the environment.
While protecting a Project: Earth project in the rainforest, Terraformer and the Force of Nature questioned and killed a man to know about the arriving New Warriors.
Terraformer joined the Force of Nature into attacking the New Warriors. Terraformer managed to buffeted and restrained Marvel Boy and Speedball in his vines which he then did to the rest of the subdued New Warriors members as Project: Earth confronted them.
Terraformer was with the Force of Nature when Firebrand II was introduced as Firewall's replacement. With the Force of Nature, Terraformer entered the war-torn Trans-Sabal to cause environmental havoc there. Project: Earth enlisted the New Warriors to enter Trans-Sabal in order to pull the Force of Nature out of Trans-Sabal. While Aqueduct killed General Halladan, Terraformer covered Nova in a deadly mold causing Firestar to hurt him badly.
Podcasts:
