Alkynes

Question 1

ALKYNES

• contains??
• general formula

Answer 1

C≡C

Cn H2n-2

Question 2

REAL LIFE EXAMPLE OF ALKYNES

used as fuel in oxyacetylene torches

Answer 2

acetylene

Question 3

REAL LIFE EXAMPLE OF ALKYNES

a naturally occurring anti-viral, anti-fungal, and antibiotic compound

Answer 3

Thiarubine A

Question 4

REAL LIFE EXAMPLE OF ALKYNES

contraceptive

Answer 4

norethynodrel

Question 5

REAL LIFE EXAMPLE OF ALKYNES

antibiotic

Answer 5

mycomycin

Question 6

REAL LIFE EXAMPLE OF ALKYNES

antifungal

Answer 6

terbinafine

Question 7

REAL LIFE EXAMPLE OF ALKYNES

antiretroviral

Answer 7

efavirenz

Question 8

REAL LIFE EXAMPLE OF ALKYNES

anticancer, and nematicide

Answer 8

phenylhepta-1,3,5-triyne

Question 9

2 types of ALKYNES + their other name

+ meaning of their alt names
+ difference

Answer 9

1. Terminal alkynes (monosubstituted) *C≡C is nasa pinakadulo so the C≡C as a whole only has 1 substituent attached
2. Internal alkynes (disubstituted) *C≡C ay nasa gitna so the C≡C as a whole has 2 substituents, 1 per C, attached

Question 10

PALATANDAAN in naming ALKYNES
in terms of:

• suffix
• parent chain (straight-chain) [2]

Answer 10

• -yne
• longest chain that passes thru BOTH C ATOMS in the triple bond (with the triple bond carbons having the lowest number)
• indicate position of triple bond before the parent name

Question 11

ARANGE the ff in terms of stability and energy:

• alkenes
• 3 types of dienes
• 2 types of alkynes

Answer 11

MOST STABLE (lowest energy)

1. conjugated dienes
2. alkenes
3. isolated dienes
4. internal alkyne
5. terminal alkyne
6. cumulated dienes

LEAST STABLE (highest energy)

Question 12

PHYSICAL PROPERTIES of ALKYNES

in general, are similar to ____ and ____

Answer 12

alkanes and alkenes

Question 13

ALKYNES have slightly ______ BP & MP than alkenes

Answer 13

higher

Question 14

WHICH will exhibit a higher BP and MP?

• linear
• branching

Answer 14

linear

*more branching = bp lowers

Question 15

2 WAYS of preparing alkynes

Answer 15

1. Industrial Preparation
2. Laboratory Preparation

Question 16

PREPARATION of ALKYNES - INDUSTRIAL

• 2 ways?
• what is formed?

Answer 16

ALKYNES formed from

1. Carbides
2. Methane

Question 17

PREPARATION of ALKYNES - LABORATORY

• what is formed?
• ^^ how (2)?

Answer 17

alkynes from vicinal or geminal dihalides

Question 18

PALATANDAAN in reactions in alkynes

Answer 18

mechanism is similar to alkenes, may exceptions or added info lang which is yung mga stated here

Question 19

ALKYNES have a _____ C≡C due to?

Answer 19

• nucleophilic
• loosely held π electrons that can be donated to an electrophile

Question 20

how MANY MOLES of reagent is necessary to convert an ALKYNE into a saturated product?

Answer 20

2 moles

saturated product = alkane

so 1 mole of reagent will break 1 π bond. since alkyne has 2 π bonds (triple bond), it would need 2 moles.

Question 21

4 REACTIONS of ALKYNES

Answer 21

1. Hydrogenation
2. Electrophilic Addition
3. Acetylide ion Formation
4. Oxidative Cleavage

Question 22

HYDROGENATION

• possible reagents (3)?

+ steriochemistry

Answer 22

H2 -> Lindlar’s Catalyst: syn addition alkene

Na or Li -> liq NH3: anti-addition alkene

2H2 -> Ni/Pt/Pd: tetra-substituted alkane

Question 23

WHAT IF 1 mole of reagent lang ang rineact sa alkyne?

Answer 23

magiging alkene yung product, rather than alkane + 1 substituent lang ang ma s-substitute PER C ATOM in the C≡C

IF, 2 moles kasi ang gamit, 2 substituents ang ma s-substitute PER C ATOM sa C≡C

Question 24

ELECTROPHILIC ADDITION - ADDITION OF HX

• what do you call the main product if 2 moles of HX is used as reagent?

Answer 24

• geminal dihalide (2 halogen atoms are attached to the same Carbon)

Question 25

ELECTROPHILIC ADDITION - ADDITION OF X2 - stereochemistry?

Answer 25

- anti-addition pa rin kahit na 2 mols ang gamitin

Question 26

DRAW the ff structures as requested by maam: 1. Alkanes 2. Alkenes 3. Alkynes

Question 27

ELECTROPHILIC ADDITION - HYDRATION - reagents? - what atoms attach to the C≡C? - mechanism? + definition + study separate keto and enol

Answer 27

- H2SO4, H2O -> HgSO4 - H, O, and H - KETO-ENOL TAUTOMERISM - rapid interconversion of enol & keto isomers

Question 28

ELECTROPHILIC ADDITION - HYDRATION - TERMINAL vs INTERNAL alkynes (what will their product be?) + which of the 2 follows markovnikov?

Answer 28

TERMINAL - 1 keto only (follows markovnikov) INTERNAL - 1 keto (double bond O is in first C in C≡C) + 1 keto (double bond O is in second C in C≡C)

Question 29

____ ALKYNES are more ___ than alkenes or alkanes due to a _____ ____ ____ character and a hybridization of ___ THIS MEANS THAT: _____ %s = electrons are ___ to nucleus = more stable _____ charge = more ____

Answer 29

- TERMINAL - acidic - higher % s - sp - higher - closer - negative - acidic

Question 30

the _____ (or removal of substituent H+) of a TERMINAL alkyne leads to its _____ _____, an ____ ____, which is an excellent _____

Answer 30

- deprotonation - conjugate base - ACETYLIDE ANION - nucleophile

Question 31

the reaction, Acetylide Ion Formation, is only applicable to what type of ALKYNES?

Answer 31

terminal alkynes

Question 32

ACETYLIDE ANION - strength of basicity/acidity? + reason

Answer 32

STRONG BASE bc it is a conjugate base of ACETYLENE (H-C≡C-H), which is a very weak acid

Question 33

ACETYLIDE ION FORMATION - study sample rxn + possible reagents (3) and their products + unique additional case? and its reagents

Answer 33

alcoholic AgNO3 -> Ag+ Na metal -> Na+ + H2 NaNH2 -> Na+ + NH3 - reaction with PRIMARY alkyl BROMIDES and IODIDES (Br & I attached to primary Carbon - RBr / RI, Tetrahydrofuran (THF)

Question 34

OXIDATIVE CLEAVAGE - reagents? - possible products (2)?

Answer 34

- O3 with Zn, H3O+ 1.) 2 carboxylic acids (internal) 2.) 1 carboxylic acid + 1 CO2 (terminal)

Question 35

TEST for analyzing ALKYNES + what type of alkynes is analyzed? + reagents + positive result

Answer 35

TOLLEN'S TEST for TERMINAL ALKYNES - terminal - ammoniacal or alcoholic AgNO3 - formation of gray ppt of silver acetylide + HNO3