Serichim technical approach to new fatting agents

Technical and Progress Meeting 22nd June 2012

Application characteristicsof fatting agents

Aims and objectives of fattening

Lubricate the surface of the fibers of collagen and interfibrillar spaces, replacing the water molecules removed with the processing and drying, so as to restore the skin to the state of natural softness and elasticity.

The fattening is crucial to make the leather have the characteristics required by the wanted product, in terms of tact, flexibility ...

Structure of collagen

• From the chemical point of view: a sequence of various aminoacids linked together by peptidic (amide) bonds.

• From the structural point of view: fibrous bundles with spatial stability due to hydrogen bonds

How fatting can be obtained

• By making a solid phase mixture between the collagen fibres and the fatting agent: physical reversible fattening;

• By reacting collagen moiety with a fatting agent able to bond with collagen aminoacids.

How collagen can be functionalised:no handle groups

Amino Acid Abundance in Mammal Skin

(Residues/1000)

Progressive abundance

Formula Chemical reactivity

Gly 329 326

inert

Pro 126 452

inert

Ala 109 561

inert

Leu 24 585

inert

Val 22 607

inert

Phe 13 620

inert

Ile 11 631

inert

How collagen can be functionalised:OH handle groups

Amino Acid Abundance in Mammal Skin

(Residues/1000)

Progressive abundance

Formula Chemical reactivity

Hyp 95 95

OH

Ser 36 131

OH

Thr 19 150

OH

Hyl 6 156

OH NH2

Tyr 3 159

OH phenol

How collagen can be functionalised:nitrogen handle groups

Amino Acid Abundance in Mammal Skin

(Residues/1000)

Progressive abundance

Formula Chemical reactivity

Lys 29 29

NH2

Hyl 6 35

OH NH2

His 5 40

imidazole

How collagen can be functionalised:carboxylic and thioether handle groups

Amino Acid Abundance in Mammal Skin

(Residues/1000)

Progressive abundance

Formula Chemical reactivity

Glu 74 74

COOH

Asp 47 121

COOH

Amino Acid

Abundance in Mammal Skin

(Residues/1000)

Progressive abundance

Formula Chemical reactivity

Met 6 986

tioether

The starting point

• Chlorinated paraffin

• Sulphochlorinated paraffins

• Fatting by physical interactions with hide

• Tanning & Fatting by chemical interactions with collagen reactive groups

Chemical interactions

R S

O

O

Cl + CollagenH R S

O

O

Collagen + ClH

The reacting functional group of sulphochlorinated paraffins is the “titrable” chloride group: which is the role of chain chlorine atoms?

Leather compatibility

Physical properties, like viscosity and density

Oxidative and hydrolytic resistance

Leather compatibility

• Mixibility of groups present in the (chlorinated) skeleton with collagen characteristics groups.

• Spatial reconfigurability of fatting agent

• It should depend on the nature of groups: hydrocarbon type or chlorinated type

• It should also depend on the “polymeric” chain lenght

Mixibility index

• There is a property that can be assumed as mixibility index?

• There are data?

• Until now we were not able to envisage a suitable test.

Physical properties

• Viscosity and density were assumed as leading properties.

• Those properties were measured for several chloroparaffins with different chain length, at different chlorination degrees and as a function of temperature.

• A model was developed to calculate viscosity and density for pure products and mixtures.

• The method was developed for chloroparaffins, and can be applied to other chlorinated fatty agents.

Property managementandamento densità in base alle temperature e ° di clorurazione

0.9

0.95

1

1.05

1.1

1.15

1.2

1.25

1.3

1.35

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55

° di clorurazione

de

ns

ità

, g

/ml

"@25°C"

"@40°C

"@50°C"

"@60°C"

andamento viscosità in base alle temperature e ° di clorurazione

1

10

100

1000

10000

100000

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55

° di clorurazione

visc

osi

tà, c

p

"@25°C"

"@40°C"

"@50°C"

"@60°C"

Equations

neclorurazio di gradoc

aparaffinic catena della lunghezza

),(),(ln

lT

clBclA

Tclcl ),(1),(

Viscosity

Density

Mixture equations

2

2

1

1

2211

1

lnlnln

ww

xx

Suggestions for future developments

• There is a general rule for predicting the viscosity and density values due to the insertion of a chlorine group in a methylenic chain, irrespective of the other functional groups?

Chemical resistance:some general considerations

• “iso” chains have to be avoided because of tertiary carbon atom reactivity.

• Chlorinated chains are protected against oxidation

• Unsaturated hydrocarbon chains should be absent

Candidate sulphonated chloroparaffin substitutes from renewable raw materials

• Saturated fatty acid chlorides• Chlorinated fatty acid chlorides• Fatty methyl esters• Chlorinated fatty methyl esters

R

O

Cl+ CollagenH

R

O

Collagen+ ClH

R

O

OCH3

+ CollagenH

R

O

Collagen+ CH3 OH

OH2

Acid chlorides as substitute

• Reactivity very similar to sulphonated chloroparaffins.

• Amide bonds and ester bonds are mainly formed

Acid chloride preparation

• Starting material: fatty acids like palmitic or stearic acids;

• Chlorinating agents:– Thionyl chloride– Phosphorus trichloride– Phosphorus pentachloride– Oxalyl chloride– Phosgene

• Catalyst: dimethylformamide hydrochloride

Main concerns in fatty acid chloride preparation

• An excess of the chlorinating agent is required;

• Big quantities of wastes are produced;

• Separation of acid chloride from the reagents/reaction co-products is troublesome

R

O

OH

+ S O

Cl

Cl

R

O

Cl

+ ClH + S OO

R

O

OH

+ P

Cl

Cl

Cl R

O

Cl

+ P OH

Cl

Cl

R

O

OH

+ P

Cl

Cl

Cl Cl

Cl

R

O

Cl

+ ClH + P O

Cl

Cl

Cl

Acid chloride plant(to be assembled)

Fatty acidmelter

Chlorinationreactor

Thyonylchloride

SO2/HClto scrubbing

Preliminary tests

• Starting material should be acid chlorides from lab chemical suppliers

• Lab preparations should be limited to fotochemical chlorination of acid chlorides

Fatty acid chloridesName Formula RN Appearence

142-61-0

205-549-1

111-64-8

203-891-6

764-85-2

213-131-2

112-13-0

203-938-0

112-16-3

203-941-7

112-64-1

203-994-6

112-67-4 Pale yellow liquid

203-996-7 (solid in winter)

112-76-5 Pale yellow liquid

204-004-5 (solid in winter)

112-77-6

204-005-0Oleic chloride CH3(CH2)7CH=CH(CH2)7COCl Pale yellow liquid

Isostearic chloride C17H35COCl-

Pale yellow liquid

74918-57-3Pale yellow liquid

Stearic chloride CH3(CH2)16COCl

Palmitic chloride CH3(CH2)14COCl

Isopalmitic chloride C15H31COCl

Lauric chloride CH3(CH2)10COCl Pale yellow liquid

Myristic chloride CH3(CH2)12COCl Pale yellow liquid

Pelargonic chloride CH3(CH2)7COCl Pale yellow liquid

Caprylic chloride CH3(CH2)8COCl Pale yellow liquid

Caproic chloride CH3(CH2)4COCl Pale yellow liquid

Capric chloride CH3(CH2)6COCl Pale yellow liquid

Photochlorination plant(operating)

Planned experimental activities

• Preparation of kg samples of chlorinated methyl esters as request

• Preparation of 50 grams samples of several chlorinated fatty chlorides for characterisation

• Preparation of about two kg samples of selected chlorinated acid chlorides.

Planned computational activities

• Development of a group based correlation for densities and viscosities of chlorinated and not chlorinated moieties.