30 August 2019 Bulletin

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Phthalic Anhydride

Phthalic anhydride is the organic compound with the molecular formula C8H4O3. It is the anhydride of phthalic acid. [1] Phthalic anhydride occurs as white, lustrous crystalline needles, and has a characteristic pungent choking odour. It is soluble in hot water, benzene, carbon disulfide, and alcohol and is slightly soluble in water and ether. [2] Phthalic anhydride is obtained by catalytic oxidation of ortho–xylene or naphthalene. When separating the phthalic anhydride from production by products such as o–xylene in water, or maleic anhydride, a series of “switch condensers” is required. It can also be prepared from phthalic acid. [3]

 


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Featured Articles

New retroreflective material could be used in night-time colour-changing road signs

A thin film that reflects light in intriguing ways could be used to make road signs that shine brightly and change colour at night, according to a study that will be published on 9 August in Science Advances. The technology could help call attention to important traffic information when it's dark, with potential benefits for both drivers and pedestrians, researchers say. The film consists of polymer microspheres laid down on the sticky side of a transparent tape. The material's physical structure leads to an interesting phenomenon: When white light shines on the film at night, some observers will see a single, stable colour reflected back, while others will see changing colours. It all depends on the angle of observation and whether the light source is moving. The research was led by Limin Wu, Ph.D., at Fudan University in China, whose group developed the material. Experts on optics at the University at Buffalo made significant contributions to the work, providing insight into potential applications for the film, such as employing it in night-time road signs. "You can use this material to make smart traffic signs," says Qiaoqiang Gan, Ph.D., an associate professor of electrical engineering in the UB School of Engineering and Applied Sciences and a co-first author of the new study. "If a person is listening to loud music or isn't paying attention while they're walking or driving, a colour-changing sign can help to better alert them to the traffic situation."

Testing colour-changing road signs at night

In one set of experiments, researchers created a speed limit sign with letters and numbers made from the new film. The scientists placed a white light nearby to illuminate the sign, and when a fast-moving car drove past, the colour of the characters on the sign appeared to flicker from the perspective of the driver as the driver's viewing angle changed. In other tests, the team applied the new material to a series of markers lining the side of a road, denoting the boundary of the driving lane. As a car approached, the markers lit up in bright colours, reflecting light from the vehicle's headlights. From the driver's perspective, the markers' colour remained stable. But to a pedestrian standing at the side of the road, the colour of the markers appeared to flicker as the car and its headlights sped past. "If the car goes faster, the pedestrian will see the colour change more quickly, so the sign tells you a lot about what is going on," says co-author Haomin Song, Ph.D., UB assistant professor of research in electrical engineering.

http://phys.org

 

EPA Begins Public Comment Period for Manufacturer Requests for Risk Evaluations of DIDP and DINP

On 16 August 2019. the United States Environmental Protection Agency (EPA) announced that it is opening a public comment period for manufacturer requests for the risk evaluations of diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP), two chemicals used in plastic production. EPA notes that the manufacturer-requested risk evaluations “are among the first such evaluations of this kind to be requested” under the Toxic Substances Control Act (TSCA). EPA is also taking public comments on additional conditions of use it identified to include in the risk evaluations. Upon publication of the Federal Register notices, comments may be submitted to Docket ID EPA-HQ-OPPT-2018-0435 for DIDP and Docket ID EPA-HQ-OPPT-2018-0436 for DINP for 45 days. EPA encourages comments on any information not included in the manufacturer requests that commenters believe would be needed to conduct a risk evaluation. EPA also welcomes any other information relevant to the proposed determinations of the conditions of use, including information on other conditions of use of the chemicals than those included in the manufacturer requests or in EPA’s proposed determinations. After the comment period closes, EPA will review the comments and within 60 days either grant or deny the requests to conduct risk evaluations. If these requests are granted, the manufacturers would be responsible for half the cost of the risk evaluations.

 

http://www.natlawreview.com

 

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