Nickel Insitute - Nickel Alloys in Organic Acids & Related Compounds

TABLE XLVIII

Corrosion of Alloys in Higher Organic Acids (Laboratory Tests)

Corrosion Rate

Type 304 Stainless Steel

Type 316 Stainless Steel

CARPENTER alloy 20

INCOLOY alloy 825

HASTELLOY alloy C

Temp.

Time

Copper

Steel

Acid

ºC

ºF

days mm/y mpy

mm/y mpy mm/y mpy mm/y mpy mm/y mpy mm/y mpy mm/y mpy

2- Ethyl butyric acid Crude acid (60%)

Nil

Nil

Nil

Nil

–

–

–

–

–

–

–

–

–

–

26

78.8

10

.08

3

.08

3

–

–

–

–

–

–

–

–

–

–

Crude acid

115

239

10

Nil

Nil

Nil

Nil

–

–

–

–

–

–

–

–

–

–

Refined acid

125

257

1

2- Ethyl hexanoic acid Refined acid

Nil

Nil

–

–

–

–

–

–

–

–

–

–

–

–

125

257

1

61

24

<.03

<1

–

–

–

–

–

–

<.03

<1

.89

35

Refined acid

150

302

5

–

–

05

2

.03

1

.03

1

.01

0.3

1.52

60

–

–

n-Butyric acid

130

266

60

+5% Acetic Acid agitated

TABLE XLIX

Corrosion of Alloys During Preparation of n-Octanoic Acid

Corrosion Rate

Type 304 Stainless Steel

Type 316 Stainless Steel

CARPENTER alloy 20

HASTELLOY alloy C

Temp.

Time

Exposure

ºC

ºF

days

mm/y

mpy mm/y

mpy mm/y

mpy

mm/y

mpy

Preparation of the acid by carbonylation of the appropriate olefin Distillation of the octanoic acid from above preparation

175

347

7

13

5

<.03

<1

<.03

< 1

<.03

< 1

230

446

5

2.54

100

<.03

< 1

<.03

< 1

<.03

< 1

TABLE L

Corrosion of Alloys in 2-Ethyl Hexanoic Acid

Corrosion Rate

Test No. a

1

2

3

4

5

6

Alloy

mm/y mpy

mm/y

mpy

mm/y

mpy

mm/y

mpy

mm/y mpy mm/y mpy

08

3 6

05 13

2 5

08 08

3 3

36 46

14 18

05 15

2 6

.08

3 5

Type 304 Stainless Steel Type 316 Stainless Steel

.15

13

.10

4

.05

2

–

–

.08

3

.08

3

–

–

CARPENTER alloy 20 HASTELLOY alloy C HASTELLOY alloy B Silicon Bronze Copper

.03

1

<.03

<1

–

–

.05

2

.03

1

–

–

<.03

<1

<.03

<1

–

–

<.03

<1

.03

1

–

–

05

2

05

2

.20

8

.18

7

08

3

56

22

15

6

.15

6

1.12

44

.18

7

.23

9

.66

26

a Test 1–1% of 98% H SO added to commercial grade 2-ethyl hexanoic acid. Solution at 90 º C (194 º F) at atmospheric pressure for 2 4 7 days with agitation. Test 2–1% of 98% H SO added as before. Solution at 120 º C (248 º F) at atmospheric pressure for 7 days with agitation. 2 4 Test 3–1% of 98% H SO added as before. Solution averaged 143 º C (290 º F) at 200 mm pressure for 3 days with agitation. 2 4 Test 4–Same as Test 1 except 2% H SO added. 2 4 Test 5–Same as Test 2 except 2% H SO added. 2 4 Test 6–2% H SO added; average temperature of 142 º C (288 º F) at 300 mm pressure for 3 days. 2 4

Page 43