You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Measurements of Rate Constants for the OH Reactions with Bromoform (CHBr3), CHBr2Cl, CHBrCl2, and Epichlorohydrin (C3H5ClO). Measurements of the rate constants for the gas phase reactions of OH radicals with bromoform (CHBr3) and epichlorohydrin (C3H5ClO) were performed using a flash photolysis resonance-fluorescence technique over the temperature range 230-370 K. The temperature dependences of the rate constants can be represented by the following expressions: kBF(230-370 K) = (9.94 ± 0.76) × 10(-13) exp[-(387 ± 22)/T] cm(3) molecule(-1) s(-1) and kECH(230-370 K) = 1.05 × 10(-14)(T/298)(5.16) exp(+1082/T) cm(3) molecule(-1) s(-1). Rate constants for the reactions of OH with CHCl2Br and CHClBr2 were measured between 230 and 330 K. They can be represented by the following expressions: kDCBM(230-330 K) = (9.4 ± 1.3) × 10(-13) exp[-(513 ± 37)/T] cm(3) molecule(-1) s(-1) and kCDBM(230-330 K) = (9.0 ± 1.9) × 10(-13) exp[-(423 ± 61)/T] cm(3) molecule(-1) s(-1). The atmospheric lifetimes due to reactions with tropospheric OH were estimated to be 57, 39, 72, and 96 days, respectively. The total atmospheric lifetimes of the Br-containing methanes due to both reaction with OH and photolysis were calculated to be 22, 50, and 67 days for CHBr3, CHClBr2, and CHCl2Br, respectively.
{"Chemical": ["bromoform", "CHBr3", "Epichlorohydrin", "Bromoform", "CHCl2Br", "CHBr2Cl", "C3H5ClO", "CHBrCl2", "OH", "epichlorohydrin", "methanes", "Br", "CHClBr2"]}