Nickel Insitute - Nickel Alloys in Organic Acids & Related Compounds

TABLE LXX

Corrosion of Stainless Steels by Citric Acid Containing Chlorides

Corrosion Rate

Solution

20 wt. per cent Citric Acid

20 wt. per cent Citric Acid

No Chloride

500 ppm NaCl

No Chloride

500 ppm Chloride

Temperature, ºC (ºF)

85 (185)

85 (185)

100 (Boiling) (212)

100 (Boiling) (212)

Metal

Specimen 1 Specimen 2

Specimen 1 Specimen 2

Specimen 1 Specimen 2

Specimen 1 Specimen 2

<.03 <1 <.03 <1

.10

4

.08

3

<.03 <1 <.03 <1

.03

1

.03

1

Type 304 Stainless Steel Type 316 Stainless Steel

<.03 <1 <.03 <1

Nil

Nil

Nil

Nil

<.03 <1 <.03 <1

<.03 <1 <.03 <1

5. Chloroacetic Acids The chloroacetic acids are

Corrosion data for a wide range of alloys exposed to various monochloroacetic acid solutions are contained in Table LXXI. It will be noted that Type 316 stainless steel appears to be attractive in a number of these exposures. Such an inducement for use of the austenitic stainless steels should be approached carefully. Pitting and stress- corrosion cracking in such a medium could be disastrous.

a most important product for the preparation of drugs, dyes, agricultural chemicals and as intermediates for the preparation of other organic compounds. Monochloroacetic acid and dichloroacetic acid are normally produced simultaneously and separated as desired. Trichloroacetic acid may be produced by an additional process step.

A better choice for handling

the product in aqueous

TABLE LXXI

Corrosion of Alloys in Monochloroacetic Acid (MCA)

Test a Temperature ºC (ºF) Test Period, days

1 25 (77) –

2 25 (77) –

3 60 (140)

4 18 (64) 28

5 55 (131) 1 7

6 170 (338) 22

Corrosion Rate

Alloy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

.28 .56

11 22

.18 .18

7 7 – –

.43 .69 .61 .48 .15

17 27 24 19

.05 .03 .03 .08 .03

2 1 1 3 1 – 2 3 2

.10 .08

4

MONEL alloy 400

.18 .51

7

3 3.56 140 – – .18 7 .36 14 – – .70 28 20.32 800 – – 1.27 50 – – – – .53 21 1.50 59

Nickel 200

20

– – – –

– – – –

– –

INCONEL alloy 600

– –

– – 1 4 1 – 8 – – – – –

Copper

.51 .94 .79

20 37 31

6

HASTELLOY alloy B HASTELLOY alloy C HASTELLOY alloy D CARPENTER alloy 20 Type 316 Stainless Type 317 Stainless

.03 .10 .03

<.03

<1

<.03

<1

.33

13

–

–

–

–

–

–

–

<.03 <.03 <.03 <.03

<1 <1 <1 <1

.05 .08 .05

–

.20

.97

38

2.16

85

–

–

–

–

–

.66

26

2.03

80 37

2.21

87

<.03

<1 13

DURICHLOR

.94

– – – –

– – – –

–

– 2 – –

.33 .03

Lead Silver

– – – –

– – –

– – –

.05

1 – –

– –

– –

30% Nickel Cast Iron

NICHROME V*

a 1–Laboratory test in 60% monochloroacetic acid liquor from a process containing 1.5% acetyl chloride, 0.5% hydrogen chloride and the remainder acetic acid. Light agitation. 2–Same as No. 1 with high agitation. 3–Field test in MCA liquor comparable to that of Test No. 1 4–Field test in tank containing 78% MCA in water with moderate aeration 5– Field test in same solution as Test No. 3, but with no aeration. 6–Field test in refined MCA in storage tank. *Trademark of Driver-Harris Company

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