In 1937, the German scientist “prof. Otto Bayer” and his co-workers was find out the poly addition reactions1-4 where the polyaddition of diols and diisocyanates in the presence of catalyst to proceeds completely to forms a polyurethanes (PUs) in the presence of mild conditions to avoid the undesired by products. Hence, prof. Otto Bayer was recognized as a “father” of polyurethanes. At the time of during World War II, for aircraft coating purpose in small-scale PUs was used but that time polyisocyanates not available in market. After that the World War II, some research groups focused on their activities and interests in PUs establishment in various countries like U.S.A and U.K but the commercial development is very slow. However, the German …show more content…
Because of limitless industrial importance of PUs, hence need to study diisocyanate chemistry briefly and understand the properties and their reactivity. Mainly the isocynates are highly reactive and allow to forming urethane groups without any by-products formation. This isocyanates contains two or more –NCO functional groups for one molecule is called as diisocyanes or polyisocyanate respectively. The industrial important monoisocyanate compound is methyl isocyanate (MIC), majorly used to manufacturing of pesticides but this isocyanate is extremely hazardous which is responsible to Bhopal disaster, in 1984. All diisocyanate are liquids or solids in the nature and highly reactive, it undergo reaction across the double bond C=N of the –NCO group. The reactivity of the isocyanates are mainly depends on the electron density of the central carbon atom of the isocyanate, the low electron density of central carbon atom contains compounds are highly reactive means the aromatic diisocyanates are highly reactive than aliphatic because of resonance structures. Therefore, the electrophilic nature of the aromatic diisocyanates can alter through different substituents on aromatic ring like electron withdrawing or donating groups. The reactivity of diisocyanates plays important role to synthesis of polyurethanes because the possibility to form dimers, trimmers and higher oligomers and also possible to form polymers. In addition, the number of cross-linking reactions may be take place, mainly depends on the reaction conditions such as temperature, catalysts, the structure of the alcohols, amines and isocyanates. Commonly used some isocyanates structures are shown in figure 1.2 that is toluenediisocyanate (TDI),
Cadet Eric Wiggins Date: 18 September 2014 Course Name: Chem 100 Instructor: Captain Zuniga Section: M3A Identification of a Copper Mineral Intro Minerals are elements or compounds that are created in the Earth by geological processes. The method of isolating metals in a compound mineral is normally conducted through two processes.
The goal of this experiment was to isolate three different molecules (acidic, basic, and neutral) from a mixture and identify their molecular structure. This was accomplished by using acid/base liquid extraction and H NMR analysis. The neutral component of the unknown mixture #191 was fluorenone. This was evident due to an H NMR spectra that had a high presence of hydrogen signals in the 7.2- 7.7 ppm range. Chemical shift values for fluorenone stated in the lab manual were 7.27, 7.47, 7.48, and 7.6 (CITE), indicating that the corresponding H NMR spectra for the neutral unknown is of this chemical.
It is often wondered how the German
Chem 51LB Report Ngoc Tran - Student ID # 72048507 The purpose of this lab is to examine the composition of three components of gas products of elimination reaction under acidic condition by conducting the dehydration of primary and secondary alcohol, and under basic condition by conducting the base-induced dehydrobromination of 1-bromobutane and 2-bromobutane. Then gas chromatography is used to analyze the composition of the product mixtures. Gas chromatography (mobile phase) is used to analyze the composition of three components of the gas products. A syringe needle with gas product is injected into the machine, and the component is eluted and the composition is related to the column or the peaks.
Chem 51 LB Experiment 3 Report Scaffold: Bromination of Trans-Cinnamic Acid 1. The goal of this experiment was to perform a halogenation reaction through the addition of two bromides from pyridinium tribromide. This was accomplished by reacting trans-cinnamic acid with pyridinium tribromide. After the reaction took place, melting point analysis was conducted to find out the stereochemistry of the product, which could either be syn-addition, anti-addition, or syn + anti-addition. 2.
The purpose of this experiment was to prepare an unknown Grignard reagent and then identify the product by molecular weight and melting point. An IR reading was taken to further identify and validate what product was formed. DISCUSSION AND CONCLUSION Organometallic compounds consist of a carbon that is attached to a metal. The carbon atoms are strongly nucleophilic because of a partial negative charge that they carry.
You know very well. Deutscher, of course! Who else? Not that fool weakling Keith. We got an iron man now, a man with guts!"
Nevertheless, the latter is not used in this experiment since it is very reactive and extremely flammable. On the contrary, NaBH4 is relatively mild and it can be used with protic solvents. In this manner, 1.507 grs of the ketone 9-fluorenone were mixed with 30.0 ml of 95% ethanol in a 125 ml Erlenmeyer flask. The bright yellow mixture was stirred during 7 minutes until all the components were dissolved.
Abstract – Methyl trans-cinnamate is an ester that contributes to the aroma of strawberry. It can be synthesized by an acid-catalyzed Fischer esterification of a methanol and trans-cinnamic acid under reflux. The solution was extracted to obtain the organic product, and evaporated residual solvent The yield was 68%, but there is some conflicting data regarding the purity. The melting point, IR, GC-MS indicate a highly pure desired product whereas 1H NMR shows there are unreacted reagents still present.
C6H12 Possible side reactions: C6H6 + nH2 → cracking products C6H12 (benzene) ↔ C6H12 (methyl cyclo pentane) C6H6 + nH2 → C +
In this experiment, it was possible to produce the major products from bromination of acetanilide and aniline. 0.075g of 4-bromoacetanilide and 0.156g of 2,4,6-tribromoanilne were collected from bromination of 0.07g acetanilide and 0.05g aniline with the percent yield of 67.57% and 88.1% respectively. At the end of the experiment, to prove the formation of the major products, melting point of the products were measured. The melting point of the product from the bromination of acetanilide was 164.8-168.50c, which is in the range of the melting point of 4-bromoacetanilide, 165-1690c, as reported on the Chemical Book, CAS Database List (chemicalbook.com). The melting point of the product from the bromination of aniline was 119.8-121.90c, which is in the range of the melting point of 2,4,6-tribromoaniline, 120-1220c, as indicated on PubChem, Open Chemistry Database (pubchem.ncbi.nlm.nih.gov).
Abstract Properties Synthesis Applications Future Introduction Poly (ether sulphone) also called PES is an amorphous thermoplastic that has properties comparable to polycarbonates. However, polyether sulphones are more heat resistant and have other properties that make them suitable for a variety of high temperature applications especially those requiring service in excess of 200 oC. The polyether sulphones were first made by the Union Carbide Corporation, a subsidiary of Dow Chemicals, in 1965. The material made was registered under the name “Udel®”.
Dichloro acetate (also known as DCA) has been predicted by many scientists to be the potential alternative cure for cancer since it was found that it killed the human cancer cells in a rat. However some scientists are not sure yet as to whether the treatment is the best solution because the human being studies have not been completed yet. Some scientists are against it because of its harmful side effects such as nerve functions. DCA is the said to be an acid, an analogue of acetic acid in which the three hydrogen atoms of the methyl group have been replaced by the chlorine group (2). DCA attacks the cancer cells and make their energy throughout the main body of the cell.
Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.