Bluefly has a bunch of work-appropriate vegan sweaters on sale, such as the left pictured Autumn Cashmere pintuck detail cardigan sweater. Perfect to wear with trousers. Put a camisole under it or a short-sleeved collared shirt (it has 3/4 sleeves). Made from 100% cotton. The cardigan comes in the pictured "peacock," yellow, navy blue, and black. Originally $120, Bluefly has it on sale for $72. Find it here.
For a more casual look, I like Autumn Cashmere's puffed sleeve sweater. It also has 3/4 inch sleeves, and, as evident by the right picture, a very low v-neck that will require a camisole underneath. It's made from cotton and a bit of spandex. The sweater comes in the pictured "seagull," a purple, navy blue, and black. Originally $120, Bluefly has it on sale for $ 72. Find it here.
Finally, for a bit of a combination of the above two and something perfect to wear under a suit, especially if you anticipate removing the jacket sometime during the day, check out Autumn Cashmere's pintuck detail sweater, pictured left in the "blossom." Made from 100% cotton. It also comes in a blue. Originally $121, Bluefly has it on sale for $73. Find it here.