1. Report 09242007: Long stability-soy based biodiesel (B100)
By Haiying Tang

2. Chemical structures of antioxidants
Ionol BF200: mixture of Mono-, Di-, and Tri- tert-butylphenol
-(+)-Tocopherol

3. Induction Period

4. Viscosity

5. Kinematic viscosity ( mm2/s)
Kinematic viscosity ( mm2/s)
Antioxidant
Indoor
Outdoor
Control
2-mon
4-mon
6-mon
9-mon
blank
4.321
4.291
4.326
4.364
4.419
4.292
4.299
4.319
4.329
α-T
4.381
4.35
4.353
4.373
4.396
4.339
4.352
4.384
4.423 IB
4.295
4.325
4.307
4.288
4.306
4.322
BHT
4.302
4.323
4.313
4.331
4.312
4.293
4.317
4.334
BHA
4.315
4.344
4.379
4.297
4.33
4.394
DTBHQ
4.298
4.3
4.304
4.311
4.314
4.303
4.309
TBHQ
4.316
4.318 PG
4.324
4.338
4.363
4.361
4.346
4.337
4.369 PY
4.348
4.32
4.377
4.332
4.301

6. Acid Number

7. Acid Number Acid Number ( mg KOH/g) Antioxidant Indoor Outdoor Control
Acid Number ( mg KOH/g)
Antioxidant
Indoor
Outdoor
Control
2-mon
4-mon
6-mon
9-mon
blank
0.176
0.217
0.245
0.27
0.296
0.214
0.233
0.242
0.282
α-T
0.224
0.238
0.205
0.225
0.239
0.263 IB
0.212
0.223
0.234
0.209
0.229
0.237
BHT
0.211
0.22
0.23
0.246
0.244
0.232
0.243
BHA
0.203
0.194
0.235
0.204
0.216
0.228
DTBHQ
0.208
0.256
0.247
0.29
TBHQ
0.222
0.231
0.227 PG
0.496
0.479
0.519
0.792
0.546
0.485
0.508
0.78
0.3 PY
0.914
0.743
0.478
0.445
0.373
0.988
0.797
0.511

8. Summary
After 9 months indoor and outdoor storage, the oxidation stability of untreated SBO-based biodiesel decrease with increasing time, while antioxidant can improve the oxidation stability of the biodiesel.
Induction period changes differ depending on antioxidant: TBHQ can improve IP and remain constant for up to 9 months, while PY and PG decrease significant.
PY and PG are not very stable at higher temperature (Summer).