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oo Sprint Wi-Fi 8:44 AM Files Grignard.pdf Pre-Lab Assignment Grignard Reaction

ID: 899379 • Letter: O

Question

oo Sprint Wi-Fi 8:44 AM Files Grignard.pdf Pre-Lab Assignment Grignard Reaction 1. Draw your complete reaction, including the formation of the Grignard reagent and the reaction with your carbonyl compound. Below each reagent, write its mollecular weight and density (if a liquid). Also write how much of each material you will use in mL [if liquid], grams, and moles. Also include the molecular weight and melting point of your final product. 2. How many moles of Grignard reagent are you synthesizing? What mass of water could fully react with that amount of Grignard reagent? What volume of water would that be? 3. Step 11 of the procedure is called trituration and is used to extract any nonpolar impurities from your crude product (petroleum ether is a miture of different isomers of pentanes, hexanes, and heptanes). Considering the possible side reactions that can occur, draw the structure of the likely non-polar side product that you are removing in this step? Courses Calendar Todo Notifications Messages

Explanation / Answer

1. Reactions, and data table for each experiment

a)                            PhBr        +            Mg          -------> PhMgBr        +        Benzophenone    -----> (Ph)3COH

moles                      1.25                      1.35                       1.25                             1.0                              1.0

molar mass          157.0079               24.305                   181.31                       182.217                      260.33

density(g/cm^2)       1.5                           -                          1.14                            1.11                           1.20

grams                    196.26                   32.81                    226.64                       182.217

volume                  130.84                       -                        198.80                        164.16

Amount of water that it reacts with : 1.25 mols x 18 g/mol = 22.5 g = 22.5 ml

b)                            PhBr        +            Mg          -------> PhMgBr        +        Benzaldehyde    -----> (Ph)2CHOH

moles                      1.25                      1.35                       1.25                             1.0                              1.0

molar mass          157.0079               24.305                   181.31                       106.121                    m.p. 69 oC

density(g/cm^2)       1.5                           -                          1.14                            1.04                          184.23

grams                    196.26                   32.81                    226.64                       106.121                        1.103

volume                  130.84                       -                        198.80                        1102.04

Amount of water that it reacts with : 1.25 mols x 18 g/mol = 22.5 g = 22.5 ml

c)                            PhBr        +            Mg          -------> PhMgBr        +        ethylbenzoate    -----> (Ph)3COH

moles                       2.5                      2.7                       2.5                                1.0                              1.0

molar mass          157.0079               24.305                   181.31                       150.17                         m.p. 162 oC

density(g/cm^2)       1.5                           -                          1.14                            1.05                          

grams                    392.52                   65.62                    453.27                       150.17

volume                  261.68                       -                        397.61                        143.02

Amount of water that it reacts with : 2.5 mols x 18 g/mol = 45.05 g = 45.05 ml

2) Given below in the data table the mole of PhMgBr forming in each case. the mass equivalent to it.

The amount of water in both g and ml that will react with each grignard reagent.

3) In each case the nonpolar product isolated would be C6H6 after reaction of PhMgBr with H2O